Tolkien observed, quite correctly, that the story of evil times requires a long time to tell. While the story of good times is all too quickly told. I suspect if your world was truly free from evil, that it would be a lot more boring than you think.
Without evil in the world save for the occasional act of folly which, if it was foolish enough, would be mortal to all parties involved, there would be very little conflict.
Lawful good people and chaotic good people would have disagreements over the best way to organize society, but these disagreements would tend to be made in mutual respect and due considerations and would tend never to erupt into violence. Persons noting the hard feelings and resentment they felt to their fellow man would very quickly be moved to repent and make restitution - even in cases where they felt the other side was in the wrong. Both sides of the argument would believe that they were required to be merciful even to their enemies. Both sides would believe that they are required to view the positions of other people with compassion.
The sort of tensions this would create would be barely recognizable as tension or drama to a person from this world.
People who were unintentionally cruel would respond like Jean Val Jean and heroically strive to undo the harm that they'd done. People who were foolish would, being generally inclined to humility, would respond with contrition and service. People, not blinded by their own arrogance and with clear proof of a person's good intentions (otherwise, they'd be dead or dying), would be inspired by these examples. Charity would abound. The community would rally behind every individual, and every individual would rally behind the community.
Good people already tend to live in literal mortal fear of falling into evil, although this tends to be mitigated by the idea that good is merciful, the notion of eternal damnation is a very real fear of the consequences of falling into evil blindly and without repentance. Even those persons who don't believe in eternal damnation are still very much grieved when they feel they've come short of the righteousness they ought to strive toward. Watching a child, who is lost but still your child slowly wasting away and throwing their life away isn't at all a hypothetical experience.
As for 'hating the plague for doing this to you', I think you have no understanding of what you are saying. You are allowed to hate evil, and still be good. Indeed, not hating the evil that evil works on people would be a sort of evil. Good never takes pleasure in other people's misery.
But this plague appears to be a righteous plague, destroying not indiscriminately but in response to a person's failing. I fear you don't understand good at all if you think good people would resent that or that it would 'do something' to them. If indeed the plague only destroyed evil, people would tend to say, "The judgment of the plague is good and true. Well earned is fate, for in my vanity I neglected my duties to my fellow man. The suffering I caused others is merely revisited on me. Now I must await my death in humility, and do my best to use the time I have remaining, and die with dignity as befitting a justly condemned man. Let us all learn from my example, and hasten to the day when the world never knows the darkness of this loss, and all persons live with each other in a spirit of love."
On a larger scale, nations grow ever more authoritarian, secure in the knowledge that however draconian they might be in their enforcement of The Law, they're still doing The Right Thing.
Wait.... what? That's ridiculous. The moment any governor or ruler became secure in the knowledge that whatever he did was just, he'd catch the plague and die from hubris. Good rulers cannot serve the law blindly, otherwise they are merely Lawful Neutral. And even a Lawful Neutral ruler cannot enact whatever draconian law they imagine, without being LE. Good doesn't believe the authority of law derives from its authority alone, but from its goodness. If the law is not just, fair, and generally beneficial - it's not good. And law that is not tempered by mercy is not good.
The wilds are even more dangerous than before; without tribes of evil humanoids hunting monsters for food, unaligned beasts swell in numbers.
But that's a short term consideration, and I'm not sure that follows. Without tribes of evil humanoids engaged in wars and banditry, and without brutal evil nations sapping their strength, the basically good nations prosper far beyond they have ever done before. Neutral beasts acting out simple drives and needs for food, generally cannot out reproduce agrarian societies nor survive against advanced civilization. Like the sabertooth cats and large carnivores of the real world, they will be ultimately driven back into small wild preserves with abundant game resources where rangers (probably Rangers) will carefully prevent outbreaks into the civilized areas beyond. The worst will likely go extinct, easily hunted down by (for example) flying mages armed with wands of lightning bolt that are secure in the knowledge that mere beasts lack the ability to strike back. Occasionally tragedies may still happen, but they'll be greeted with the same grief and outpourings of compassion scene when deaths are caused by tsunami's or avalanches. In even the short run, the balance will radically tip in favor of the good aligned nations unless you have some sort of rampaging epic super beasts - but if you did, its unlikely that goblins were what was keeping them in check in the first place.
Adventuring would experience a boom, what with all the former evil lairs suddenly empty. Delve the ruined drow cities and recover their treasures, or seek out the lost hoard of a dead red dragon.
But why would it experience a boom? What good possibly could come of delving into ruined Drow cities to recover their treasures? Is mere greed and lust for power to continue to rule the day after evil has been wiped from the world? Why would you seek the lost hoard of a dead red dragon? Did you even read 'The Hobbit'? I mean half the book is devoted to Thorin's folly in seeking foremost the Dragon's treasure rather than seeking what he ought to seek, which is the restoration of justice. Only Bilbo in his humility avoids the folly and greed by disregarding the treasure - indeed giving his whole share away - in order to restore justice and goodwill among the communities that were ravaged by the dragon. In a world were good is the order of the day, Thorin and company get sick as soon as they lay plans of greed and folly and disregard the good advice of Gandalf. It's not clear whether repentance causes you to recover from the plague, that is, it is not clear if you can be redeemed in the world you envision, but in a world where falling into evil causes you to get visibly ill (rather than invisibly ill), it's generally going to be quite clear whether you need to repent.
I mean, just imagine the Hobbit without greed and folly in it, and what's left of the story? There is no dragon, so Bilbo isn't overcome with cowardly fear of the dragon at its beginning. But then again, neither has Bilbo fallen into sloth and arrogance at the beginning of the story, and to the extent that he has just a little bit and needs a change of perspective, Gandalf doesn't need to resort to a bit of well intentioned trickery for Bilbo's own good. The dwarves, already inclined to listen to Gandalf, have no reason not to accept Bilbo's companionship. Bilbo, lacking a reason for great fear (except maybe thunderstorms and short rations) agrees to set off for the same reasons of inner courage he found to face the dragon. They have no more adventure getting to Rivendell than getting wet and possibly losing a few ponies, because they have no trolls to fight. Armed with the wisdom of Elrond, they cross the mountains with no more than a scare in a thunderstorm, because their are no goblins to fight. Thus, they stay on the path they need and require no rescue by the eagles, nor replenishment by Beorn (or his people, as he now has no reason not to marry). Gandalf doesn't need to leave them to face the necromancer, but if he does, they have no need to even face the dark of Mirkwood as the only reason they do is to avoid hobgoblins in the north. And if they do face Mirkwood, they come through its adventures to the halls of Thranduil - who has no reason to mistrust dwarves nor does Thorin give him a reason because he has no need to lie or keep secrets. The dragon is after all dead, and Thorin knows that no one can steal anything that is rightly his - because the plague would take them. Nor for that matter is there anyone left alive that would take the treasure, as there is really nothing there of value at all. You can't eat gold, and what would you do with it that wasn't vanity? The whole world has come to value friendship, song, and cheer as Thorin at the end of the story admits that they should. The elves here that Thorin wants to restore his kingdom and return to the community the value of dwarves craftsmanship that they have been lacking these last decades, and everyone is happy about it. They go to laketown, Bard - having replaced the dead greedy master of the town - greats his neighbor king with a warm welcome, and says he's been eagerly awaiting this day. Then the two traipse off to the mountain to divide up equitably the treasure - breaking any curse that is on it - and mutually profiting from their trade just as the communities of Erabor and Dale did before the dragon. There is no battle of five armies, and everyone lives happily ever after.
Within the framework of the world, this new story is a story of hardship and conflict and triumph. But we'd barely recognize it as drama. The poignancy of the original work would be gone, and if you had means to compare the two you'd see that the evils overcome in the newer story were trivial compared to the original. No one learns as much wisdom, because no one ever so far departs from the path of wisdom because the temptations and dangers that lead them off the path largely don't happen. But then again, no one starts from a place where they are as far off the path of wisdom because no one has cause to be. And the whole story, condenses down to 30 or 40 pages. Of course, the pure good society probably wouldn't condense it down, and they'd fill it with smaller and pettier dramas that seemed to them to be the height of conflict, but which lacking their perspective we'd read as a petty travelogue wholly lacking in adventure. The loss of the ponies when fording a stream and the grief that the dwarves felt for the loss of such good beasts would probably be a major theme of the book. It would probably be mentioned at the end of the story how all the good results couldn't have happened without such tragedy. Thorin would probably commission a great artistic work, noting how his kingdom couldn't have come about without the brave sacrifice of the ponies. People in that world would consider it very poignant, and work hard to ensure that bridges could be built that would allow safe commerce and travel between disparate parts of the world.
That's what adventure would look like. That's how people in that world would know they weren't in utopia.
Or if you prefer a plottier game, fight for the cause of chaos and freedom against the oppressive governments.
Wait... what? All the truly oppressive governments die off in the first few months. There might be a few relatively restrictive governments, but fundamental disagreements between LG and CG are likely to be relatively small and resolved by compromise. (The compromise between LG and CG would be NG, which is to say, more good than either would be alone as each compromise would resolve a misunderstanding that drew the partisan away from goodness.) What the heck would their ever be worth fighting for? The guys in the government would be fundamentally decent, humble, considerate individuals - fully willing to look at problems from your point of view and give them due consideration. They might not always make the best choice, but they'd tend to make good choices with good intentions. They might not agree, but they'd disagree in pity, in kindness, and in love with the person they disagreed with. Whenever they argued, ultimately they'd be seeking to prevent others from folly, and if ever they felt themselves becoming aroused to wrath and frustration they'd tend to want to take a time out and go back to looking at problem's from their point of view, humbly, and with due consideration. Ok, so the tax was a little less fair than you desired it to be, and unfortunately the decent fellow you are arguing with holds a different point of view. But being a decent fellow yourself, you know why he holds the point of view he does, and you'd certainly not consider forcing your point of view on them by force. Instead, you'd engage in long wearisome debates in hopes of bringing guy around. Arguments would tend to be resolved in the favor of whoever could out nice the other in the long run.
But even better, in the long run the big difficult questions of rectifying injustice would tend to go away. Its fundamentally the nature of injustice, that it creates situations where you cannot be just without being somewhat unjust to someone else. But as the injustice trend line slowly declines toward zero, cases where there are big conflicts over how you bring about just ends would just tend to go away. Almost every contentious issue would go away as the fundamental causes declined.
Alternatively, oppressive laws might disenfranchise ever more people, leading them to run off into the wilderness to become bandits, preying on caravans because they have no other way to survive.
Seriously? Do you have the slightest idea what good is? Heck, I'm not a very good man but if a guy comes up to rob me and he isn't threatening my children or something, "Dude? You don't need to do that. Let me go down to the ATM and withdraw some cash. Tell me what you need. As long as it isn't drugs or something, I'd be happy to buy it for you. Would you like to go get a beer and some dinner with me and talk about it?" Remember, in this world people who are reduced to poverty are like serious about being willing to work for food. And people who are in the caravan are serious about, "Look my fellow Samaritan, it's a naked jew by the side of the road. We can't stop our journey, but let's at least take him to an inn, see he's clothed, fed, and provided for until we can return." In the world you imagine, when the king learns his laws have disenfranchised someone, he rents his clothes and cries out in anguish, "What have I done?", then he orders his own tableware be sold to provide for the impoverished person.
But keep in mind: everyone you kill is a decent person.
I'm keeping that in mind. You should keep in mind everyone in charge is also a decent person. Even in the real world, we find countless examples where decent people on either side refrained from killing just because they could. Even in the highly unlikely case of WWI starting because the fundamental injustices and greed that started it wouldn't happen (else everyone would be dying from the plague anyway), it would have ended during the Christmas truce in the first year. People on both sides would have been like, "If we can put aside our differences for that long, then surely we can work out a way to stop this horror." In the world you imagine, almost every violent contest stops as soon as the basically decent people on both sides look each other in the eye and agree the other is decent, and at worst ends up with lumps on the back of the losers head because the winner can't bear to kill his foe.
