Like you, I've grown tired of WoW as of late. Also, like you I've decided not to jump back into the Raiding game, which means that after completing the major dungeons of current WoW endgame, for the most part we've "beaten" the game.I still think that there is value both to classes having a well defined role, and to players being able to switch playing styles. The Final Fantasy XI game Kaziel mentions for example gave you the possibility to change from one character class to another every time you visited your house. Your different character classes had their own respective levels, but if today you weren't feeling like playing the white mage healer, you could level up your same character as black mage damage dealer instead. That gave you the choice of what to play, and the other players could see what style you were playing. In World of Warcraft the problem is often that from a distance you just can't tell. You need a healer, but the /who command only shows you who is priest or druid, and not whether they are willing or able to heal.
With that, I've been playing the Open Beta (or World Tour) in the US for LOTRO. This game is something of a contrast in class design compared to WoW. While the so called "holy trinity" is still there, instead of creating each job with a way to DPS, they gave each class pretty specific roles other than DPSing (with the obvious exceptions of Hunters and Champions). While I think each class has a certain amount of DPS abilities (such as the Lore Master's staff smack ability, or throwing the thing on fire at the enemy) they obviously fit into certain specific roles, as described on the character creation page.
I'm curious about your take on it. My feelings are that while Blizz did many things right, the decision to make each class able to spec DPS was a mistake. Mind you, having access to abilities that allow you to DPS isn't a bad thing (in fact, I think to a degree it's necessary otherwise you end up with classes that can't solo in order to make money, and they are left floundering), but when you give a job with an obvious certain role (for example Priests healing) and give them the ability to completely ignore that aspect of their gameplay (the infamous "I'm a Shadow Priest. I don't heal!" quote) you're just asking for trouble. Some might say that being given options is a good thing, and I agree. My counter to that statement is that you are given options, specifically during character creation. In LOTRO, when you pick a class, it clearly says what the job is (for example the Captain is listed as a Pet/Buffer class). The game that I know best that made classes mostly with single roles is FFXI (been playing almost since release and I'm still playing it now). When you're partying for XP, and you invite a Paladin, you know exactly what you're getting, a tank. If you invite a White Mage, you're getting a healer. There are some classes that can fill multiple roles depending on gear and subjobs, such as Warriors, Ninjas, and Red Mages, but even then, those jobs have main purposes, and really are exceptions to the rule. While every job may not have something fun for everyone, at least you know what you're getting when you invite someone, and you can pick the jobs you want and only play them.
Also, I think part of the decision making process on Blizzard’s part was the idea of "If we make some classes with DPS specs and tanking specs (or healing and DPS, or whatever) then more players will play those classes, but be willing to be flexible and do alternate roles aside from what they specced." And while this is a good plan, in theory, in practice it blows up in your face more often than not. I've lost track of how many times I've been in a group with a druid as the only healer, and they say something like "I'm feral spec. I don't heal." But then doesn't want to leave so we can get a healer. And of course there are the famous experiences of being grouped up with something like a fury specced warrior who tries to tanks dual-wielding, in PvP gear, and Berserker Stance.
At first, I wasn't going to send this email because it was quite similar to your post "Gimping your group talents in World of Warcraft", but then when I started thinking about it, I realized what I was asking about was different enough. Mainly, it's the fact that Blizzard chose one way of class design and LOTRO (along with many others) have taken a different approach, instead your post being about choices within the existing system, and your views on this.
More importantly it is the difficulty of the dungeon which determines how specialized somebody has to be to beat it. If your warrior for ramparts is level 60, he'd better be protection spec to make a good tank. If he is level 70, he'll still be fine with his twohander in berserker stance. Same is true for a healer. Being holy spec raises the "effective healing level" of a priest, being shadow spec lowers it. If there is another healer around, or the dungeon is of lower level, the lower effective healing level might work just fine. But if the dungeon is very hard, you'd better be spec'd right for the job.
So I wonder if WoW could somehow calculate a players effective healing level, based on his level, spec, and gear, and then display this instead of his character level. If people would see what they get when they invite somebody to their group, there wouldn't be so much conflict.