Over the last decade plus of using 3.X/Pathfinder I am used to having everyone at full hit points after every fight thanks to cheap wands of cure light wounds, infernal healing, lesser vigor, ect.....
Sure, but that is expending a limited resource for healing. Which does not break a sense of realism. I recall at least a couple times, we ran out of such wands, and the trip back to civilization would have been too dangerous, and we didn't have a safe place to craft such a wand.
I'm pretty sure lingering wounds will be available as a rules module. Look to recent Unearthed Arcana articles on Dragon mag for lots of 4e variants and tweaks that could be made to work with DDN.
As explained, it really isn't as good as a module add-on, as it has significant ramifications for things like 1) the inability of WOTC to use all those dozens of 1e adventures that they've been busily stating up (none assume full hit points every day), and 2) an issue with new published adventures, and 3) a problem with a shared experience amongst players of the game.
Except D&D has never modeled lasting injuries, even with slower hit point recovery, injuries never impair you. Thus hit points can't be modeling significant lasting injuries.
That's been true of every version of D&D, unless something like a Vorpal sword was involved in inflicting the injury.
I've tried to state this a few times, but I suspect I'm not saying it well. I will give it another shot. And this time, I will label it better so I can refer back to it:
NOT ASKING FOR FULLY MODELED LINGERING INJURY: Nobody is asking for a way to fully model long lasting lingering injuries in this game. That's not this game, I agree. The issue is this: On a scale of how you would set natural healing to start each day, on one side you have zero natural healing (which would be much closer to a long lasting lingering injury), and on the other you have full natural healing every day (which is as far as you can get from a long lasting lingering injury). All I am asking for (and many others) is that the default not be set at that extreme of full natural healing every day. That way, while there is not a fully modeled lasting lingering injury, at least there is a chance for a tiny little dose of it. Some way for the DM to say "Well, your arm is still bugging you a bit from that Owlbear who clawed you there, so you're not at max, and you will need to expend a resource to healing fully up if that is an issue".
Agreed but it has never been so grave a wound as to cause any impairment. The worst the rules have ever effectively modeled is a scratch or bruise.
The impairment is the cost of limited resources. Hit Points are, of course, an abstraction that does not perfectly model this. But, at least not being at full hit points can provide some small thing to hang your abstraction on for an injury of some kind.
The rules have never really supported the GM's descriptions of dire wounds, except when they actually lead to death.
Considering hit point rules have never made no sense for modeling grave, impairing or lasting injuries, if anything previous editions where hit point damage remain for extensive periods of time unless cured by magic makes even less sense than the newer rule.
I can see what you want and even agree with it, but logically it isn't justified by the rules of earlier editions, these rules make more sense, they just don't "feel" right.
I disagree, that don't make any more sense than any other rule. Not being at full hit points, being at full hit points, neither makes much sense for this topic. I'd argue at least "not being at full hit points without the expenditure of a limited resource" allows for SOMETHING, however small, to hang your injury on. But even if you think it doesn't make sense, I don't see how it makes LESS sense than natural full healing after 8 hours. At worse, they make an equal amount of nonsense. So, the baseline should be set at what's best for the game. Which is what all my arguments have been - it's best for the game to have at least some chance you won't be at full hit points, for the reasons I stated above (past adventure utility, future adventures, common experience for players, ability to house rule in both directions rather than just one, etc..). These are all, "best for the game" arguments rather than "what models lingering injuries best" arguments.
Admittedly I haven't been following the details of the healing rules in the last few iterations of Next, but I don't see how what you describe is very, even any, different from 4e.
If that is correct, then it's not any special cultural change at least for 4e play.
Yes it is true that 4e had this. However, one goal of 5e is to bring in fans of playstyles represented by all the editions. And to further that end, WOTC has been stating out 1e modules lately, for example. Given that all editions of D&D except 4e required either the expenditure of a limited resource or luck to get back to full hit points after a 8 hours rest, I think it makes sense to make the default at least something less than 100% certainty of full recovery. Which is why I proposed something like rolling all your HD to see how much you recover in HP (and others proposed getting back some hit points and all hit dice, so you could expend those hit dice to get back to full right away). Odds say you will, roughly, recover all your hit points anyway. It's just that it would introduce some amount of chance that you could have a slightly more lingering type of injury, which makes the game far more emulative of a certain playstyle enjoyed by the other editions of D&D. It's a compromise - one that is a relatively minor change for 4e players, but the reverse is a relatively major change for non-4e players (for the reasons I've stated above).
Of course, the following reflects only my POV and should be treated as such, but having said that...
People (like the OP) unhappy with how healing currently works seem to think the conundrum of injuries vs healing can be resolved by only looking at the healing part, i.e. if healing is slower and/or doesn't heal you to full HP, it wouldn't break suspension of disbelief.
IMO this is where they are mistaken. Not that the system as it currently stands makes it very hard to suspend disbelief (it does IMO), but in the fact that damage can continue to be simulated as it always has been and that the solution resides solely in fixing healing.
Case in point: a fire-breathing dragon. No matter what level you are, how many HP you have..., if you take enough damage from a dragon's breath, you're toast (literally, in the red variety case). You could require 10000 days to heal from that, outside of explicit use of magic, your PC is dead. End of story.
What's my point? In order to have a satisfying healing system, damage can't all be treated in the same way. Being hit by a club and being fire-breathed by a dragon should have clear, different consequences beside the amount of damage dealt.
But because of many factors...
1) the sheer complexity creep of taking sources of damage into account;
2) the fact that players, in general, despise having "minuses" applied to their character sheet, be it in the form of attribute penalties for certain races, ability drain from undead and other monsters, etc;
3) the fact that many players want to play a game where magical healing isn't a prerequisite;
...this will never happen, I think, outside MAYBE of a module.
The only simple solution I see is to require magic for any healing (maybe over a very small threshold) at all, but that would not be well received by many people.
Well first, I am the OP, and I disagree that I failed to address this. I did address this issue, though perhaps I didn't phrase it well. But, I hope my responses above help to address it better now.
As for "the only simple solution is magic" portion of your answer, I disagree. There are other simple solutions, and we've discussed a series of them. You could roll for how many hit points you get back, introducing an element of chance. You could get back some hit points and all your hit dice, introducing the expenditure of a limited resources that is not magical in nature. There are simple ways to introduce a mechanic that at least allows for a chance, however small, that you will not start the day at full hit points and must expend a limited resource to get back to full.