Best what? Best selling? That goes to 5e. Most groundbreaking? OD&D. Most supplements? At a guess, 2e. I can't think of a single category I'd put 4e as "best", even "best at achieving a specific vision" is misleading because it values the vision they had. About the only thing I can think it achieved was the most radical change in the nature of the game ... but even that is my opinion.
Was it the best version for some people? Certainly. Arguably the best? Sorry, I don't buy the objectivity of that label.
Let's look at the game from the DM's side. Has there ever been an easier edition to create encounters with? You could take any existing monster, and applying a small amount of discretion, increase or decrease their level to make them suitable for your needs. No need for "bounded accuracy"- if I want my 11th level party to fight Goblins that present a legitimate challenge, behold, level appropriate Goblins that I don't have to sit down with for an hour choosing Feats and skill points, unlike 3e.
How about actual Stealth rules? It took them awhile to get there, granted, but the edition closed with Stealth rules that functioned once you understood the difference between something not being visible and something being hidden.
I could go on, there's certainly more, the issue comes down mostly to a few factors. Those people who do not want a game designed to be a game first, with little attention given to the game as a simulation. Or who want weak heroes, struggling to survive, afraid of a goblin's shadow at the start. Who want players who have to manage resources as opposed to not only usually being ready for a fight, but with a game designed with the idea that characters enter battle at close to top condition. No need to figure out if you're going to accidentally TPK your party if they barely survived encounter 3 when you had encounters 4 and 5 planned, outside of extreme circumstances!
If you as a DM and your group like big, cinematic-style setpiece battles, each character having an arsenal of tactics more complex than "I swing my sword 2-4 times", classes balanced against one another, clear action economy, and clear rules that aren't murky and ambiguous, with transparent designer intent, 4e was just the system for you.
If you as a DM and your group wanted to quickly resolve things like traveling from point A to point B or shaking down the local Mob or meeting with the King, 4e could do that as well. Yes, yes, the math, I know, but what version of D&D hasn't shipped without flaws? It was simple to fix once you knew about it, if you cared. If you didn't, like say, you liked the idea of PC's being a little on the back foot, then you didn't. Or forced the PC's to use up one of their 16 or so Feats, horror of horrors.
I understand that there were people who didn't want the game. They didn't want character classes that tell you what your job in a team game is, or actually having abilities that allowed you to perform said job. Marking foes as opposed to just "standing in a doorway", for example. People who prefer not to use battle maps, or want more attention given to social and exploration than 4e gives. I mean, every other edition of D&D has done so well with that regard, right?
If 4e didn't suit your needs, that doesn't mean it wasn't well designed. It certainly has better design than the current edition, with problems that haven't been addressed in 12 years now in the PHB, rules with the consistency of oatmeal, or a Bethesda-like attitude of "hey, we don't need to fix our game, our
modding commmunity DM's and 3PP developers will handle it for us!" If 5e is so great, why do we have Level Up or Tales of the Valiant?
Because if there was an edition of D&D that completely met the needs of an entire gaming group, without copious redesign, that person is playing that edition and probably not on this forum. I'd imagine, at least. I mean, playing D&D is better than griping about it, isn't it?
And in case you think that's hypocritical of me, since I was very clear about what I think of 5e just now, it's not. I love D&D. I have fond memories of D&D. But D&D has never been perfect for what I need it to be. I have fond memories of 4e, because it was, for me, the easiest version of the game to DM. It could be fun as a player as well, because I love crunch, choices, options, and tactical setpiece battles with a bag of actual tricks at my disposal and decision more pressing than "do I use my Action Surge, Second Wind, or three Superiority Dice in this battle or go without since I'm unlikely to get an hour nap in this goblin warren?".
But even then, I didn't really like Skill Challenges. And when I tried to run a classic dungeon crawler in 4e, it was a disaster. News flash, that hasn't changed with 5e either, since every level 5 Wizard can just create an invulnerable barricade to nap whenever they want, unless I want to make sure there's always an NPC with Dispel Magic around, even if it would make zero sense, or I want to create some kind of "antimagic zone" or other such.
And I hated bad templating with Reaction powers, and the higher tier Reaction/Interrupt gameplay which reminded me too much of MtG. Or having to clearly ask DM's and players what their powers specifically say they do, because some chucklehead thought a "Reaction in response to being targeted by an attack" was somehow fundamentally different than an "Interrupt in response to being hit by an attack". Bah!
Bottom line is, 4e was a good game. Obviously, it wasn't the game some people needed. That's fine, no need to impugn it because of that fact. As I said, if there ever was a D&D that everyone needed, then why aren't people just playing that game, then?
