What they ARE looking to revolutionize is how an MMO is going to FEEL. I'm kind of like you, actually. The reasons that I became jaded with MMOs in general was because there was little beyond the gameplay aspect, be it combat, character development, or PvP. Menial tasks (I'm thinking primarily killing monsters and dispatch quests) to obtain experience to improve your character were give such shallow context that it was equivalent to no context at all. I won't even touch the subject of grinding. Granted, there were some inventive quests that I played in WoW, but they all seemed so insular and insignificant in the grand scheme of things. Indeed, they were, because there really WAS no grand scheme. It all boiled down to: Arthas left the world in chaos...let's muck around in the chaos and kill things for people to make them happy. And it was only slightly different on either side, much less the races. Correct me if I'm wrong, but the Burning Crusade didn't add much, and the Wrath of the Lich King comes too late (for me at least) to add a coherent storyline if it does at all.
So you have to ask yourself: is the reason that people rushed to endgame with alternate characters (or even their first ones) due to the leveling system, or because there really wasn't much to the game beyond getting better stuff with high-level characters so you can look all shiny and kill people/things better? And as a result, much of the interest in the endgame is going and killing high-level stuff with other high-level characters, preferably in guilds to make it easier to find people. And thus we have the beginning of guild drama, almost a necessary resort when endgamers don't have much else to do.
I really think that's the area that Bioware is trying to bring to the MMO arena. They've had experience with creating games that have focused on stories and context. If you need convincing (I hope you don't), just try Knights of the Old Republic or Baldur's Gate 1 or 2, if medieval's more your style. By creating a game that is so content-oriented such that every class on either faction and each moral path will get different stories, there is a HUGE number of possibilities that can be explored. Not to mention, when things you do or say before or after a quest have an effect on what happens to you, characters are being developed in the process. People replaying the game with alternate characters won't have to rush through the game to level up because, although the places they see won't necessarily be new (although I suspect there will be new places for you to explore if you follow a different path - it would only make sense), they'll be basically playing an entirely new game with the same game mechanics they were used to.
I expect that they'll probably keep some of the endgame aspects of WoW, just because that IS one of attractions of continuing with the game: you get to feel extra special and extra powerful. You can go conquer big nasties, see lots of cool special effects, overcome a difficult boss, and get even shinier stuff, as gamers are so wont to do. But what Bioware doesn't depend on is just adding more and more stuff for the endgamers to do just to keep people interested, or higher levels for people to achieve. They assume that people will want to explore more of the game world by playing other classes, and thus other stories. And even better: guilds and groups will consist of multiple people, each with their own special story based upon their decisions in the past, playing together to do bigger things (I assume there will be an over-arching story of the Sith vs. the Republic that links everything together). No longer will people get into guilds solely for help leveling up and a dependable source of people to go into an instance (or, most likely, just less so). Guilds and groups spring up more because people want to play through the game's story(ies) together. Or maybe I'm being all too idealistic and optimistic about Bioware. I'd prefer people to wait and see how these innovations play out and how massive amounts of content will be infused in an MMO. Story's basically been ignored, but if Bioware's successful, I think it could be at least genre-changing, if not genre-defining.