But classes have traditional been a set of strengths. Roles are a construct, a way of looking at how people perform in combat.
So, roles are a construct, but classes are not? That's just silly. Classes are constructs, which were originally directly linked to their roles (cleric was the only healer, magic-user was the only artillery, and fighter was the only front-liner to stop that ogre from eating your face).
Most classes in most class-based games have allowed you to easily perform multiple roles without much of a problem.
Let's see some citations here. Provide the list of class-based RPGs in which you can easily perform multiple roles with a single class without sacrificing things in return. That's what 4e's multiclassing is all about: you sacrifice direct power within your role in order to take on a secondary role.
It is far more exctiing this way.
For you. See, I like sitting down with a group of people and working together because of our disparate capabilities (the very reason for a class-based system). When one guy can do everything that the rest of us can do, combined, I see no reason why we should be playing a group game, since he can handle it all, nor do I see why we should be playing a class-based system, since he has no niche weakness for his compatriots to shore up.
In 3E and AD&D what you are saying isn't true. A fighter was simply someone who could hit hard, and live long; but that didn't mean he always had to just stay in the front line and tie people up.
You're right about 3e, since 3e seemed to think "Fighter = All Combat Possibilities" (which didn't always work, since the majority of two-weapon Fighters would dip into Ranger for that front-loaded benefit).
You're dead wrong about AD&D, especially in regards to design intent, as Gygax clearly stated in the DMG that a fighter that isn't acting as a defender isn't fulfilling the function of the fighter and should be docked experience for it (same with the cleric that refuses to heal and support his party).
3e had lots of balance issues.
That's putting it mildly.
But 4e wasn't an improvement, it was a regression.
A regression that casts aside decades-old "tradition" in order to implement design philosophies from the most recent decade is most assuredly an improvement in my book.
3E was a serious innovation in gaming.
Yes, it was. I won't dispute that. However, it was still hampered by a number of "because it's always been that way" design ideas that kept it clinging to a 30-year-old design.
It really brought the class and skill games together.
It most certainly did not. Class systems are predicated upon a chosen role that provides you with your benefits and your weaknesses in a neat package, while skill systems are predicated upon you building whatever you want from the pool of components available to you.
Made a system that functioned well in multiple genres.
That's a matter of opinion. Some people think d20 works perfectly for anything under the sun. I think it's incredibly poor at anything but heroic fantasy games.
4E isn't an attempt to improve that system, but to return to the simplicity of basic D&D.
Yeah, it's an attempt to turn a game back into a game, instead of a highly complex math exercise.
That said, I think 4E is a good system. But really should have been marketed as a seperate game entirely.
I love this philosophy. 3e was a massive change from 2e (and especially away from BD&D), as much of its elements were new to the system (while some were just evolutions of late-2e design ideas) but it's okay to bear the D&D name. 4e is nowhere near as big a change from 3e as 3e was from 2e, but it's not okay to bear the name, despite repeated references to it being similar to BD&D.
3E was a great compromise in this respect. In fact, it solved a lot of the problems inherent in a point based game, while preserving the openness and ability to customize your character.
As a fan of point-based games, I can only choke on my laughter at the suggestion that 3e solved any problems that those types of games have, as 3e is still unabashedly a class-based game with minor customization. Need a healer? No skill or customization will help you out... only choosing a class (cleric). Need a trap dude? No skil or customization will help you out... only choosing a class (rogue).