Some months ago I tried to create a list of [sometimes Massively] Multi-player Online games (Role-Playing Games, mostly) that were innovative. Below, I will list what, at least at the time, I was able to find for the list here on the database:
Multiplayer Online Games that Try Something Different
I'm willing to bet there are plenty of MMOs that have managed to change the formula significantly. Not many are popular, though, and many of the more popular ones are slavish to the expectations of people who play them (well, ostensibly slavish-- I think some developers use the users' desires as a crutch to excuse a lack of innovation). This is intrinsic in the kind of money that's being thrown around; like in films, the more investment there is, the more the investors can put pressure on the developers to do things by the book to get reliable results.
(I'll say as an aside that I think Star Trek Online seemed to hold some of that promise for me, but it turned out the previews I watched were the sum total of what was available. They promise more, but recent geological surveys have discovered that the Earth is not filled with liquid hot magma, but with unfulfilled promises. Enough fans hoping for a Star Trek experience or a cool science fiction RPG experience seem disappointed to me that I'm going to be a bit more wary in the future).
That's why the subtle changes that NCSoft says they are making for Guild Wars 2 are exciting to me. NOT because I'm likely to play the game (I need a new computer for that-- though if I had a new computer I'd totally hit that for a while), not necessarily for the innovations they promise (though exciting, I have lingering questions that aren't answered in all the interviews and dev blogs I've read about just how interactive things really are*), but because they promise innovations and potential users appear to be excited. This to me is important, because these beliefs: that users are a conservative bunch who don't want innovation, who want to craft the same way, grind the same way (some people lazily speak of grinding as if it were part of the genre itself, when it absolutely doesn't have to be), have the same features, over and over throughout eternity-- all are shown to be at least partially false. There are users out there who want something different, and many of these users are the grognards** that have seen many iterations of the same formula and, at the very least, want a strong refinement of that formula.
Arguably World of Warcraft was, for many, a kind of refinement, making the problems of past MMORPGs smaller (or even disappear). Here's hoping that Guild Wars 2 is at least a next step in the evolution of what we EXPECT from MMORPGs, perhaps to the point that there might be a bit of a branching off, and that there might actually be different camps of expectations for such games, sort of like what we get when we talk about plain old RPGs. Different genres of MMORPGs might then be on the horizon, which might allow for more willingness to innovate, and so on... assuming it ever gets cheaper for a smaller company to actually run such games.
Maybe breaking the cost barrier is the real revolution that still must to happen for innovation not to be a dirty word. As browser-based games become less of a chore to run, I can see such things not being a big deal. Then again, my current browser is such a slug that I won't hold my breath for my being able to take part.
**Spellchecker suggests I'm wrong in using this perfectly adequate term, providing me with the alternatives: grogginess, graybeards, graveyards, and groundsman, all of which might have made a more interesting, if confusing, sentence.
This article seems to address some of my questions: http://www.eurogamer.net/articles/guild-wars-2-dynamic-events-interview?page=1