Devaluing the trinity, every AT able to solo content... that kind of thing is what made CoH fun to me, and I know a lot of other people agreed. What you call incompetence, I call people being able to play the game in mathematically suboptimal ways while still succeeding. Sure people didnt need to play just their role, but if you wanted a team, it wasn't "hey, support looking for team" and waiting for a team with support open... it was looking for a team with an open slot.
These things made CoH good - not bad - and the fact that you cant find that just anywhere else is why I miss the game so much.
Indeed, I remember CO recently added a mission that forced players to bring the healer along, and man I was so miserable for it. Anytime teams were forming they'd spend thirty minutes to an hour forming the "perfect" team to do the mission. Now I feel for those who get obsoleted, somewhat, but it's more pity than anything. Times change, but I feel mmorpg players have let themselves be stuck so far in the past that everyone else moved forward and is still having fun, while fun to an mmorpg player these days has become "I got the item YES YES! preceeded by miserable "God damnit give me the item already!".
It's not the trinity itself, but more that mmorpgs never ever change. If they do something, it's a very mideocre effort because they are to scared to move forward and branch out, or dig deeper layers of depth for themselves. City of heroes actually had depth in spades, it had enough depth that it'd have a hard time climbing out of that depth.
I honestly blame the players, in the case of those who moved on over being useless because their over specialied attackless buffless healer was useless and not needed, or their taunt-only attackless tanker was useless, rather than the game, because the reality was, they weren't adapting. They wanted a game that played exactly like every single other game to the bone with only a graphical/style carpet over it. Which, defeats the purpose of designing any game to begin with. A game should be identifiable among the others of it's genre, city of heroes was known as city of heroes, not everquest clone #30.
My personal favorite quote of all time came from Warren Specter, about game developers. "We need to show them that they are lame, no matter how much money they make." He was refering to the huge amount of modern developers who just make generic games, because they really aren't true game developers. There are so many counter strike/halo clones(modern military shooters) and in the mmorpg scene, there are what many people call WoW clones that truely are WoW clones, though everquest clone should probably be the better term :/.