Jim Rossignol has some thoughts up over at Rock, Paper, Shotgun on MMO design - a study in why, despite WoW being WoW and 'the' MMORPG in a lot of ways, EVE Online is potentially a better base for future MMO designs. Not in terms of creating a better "PvP-heavy spaceship-centric world," but by applying some of their design principles to games with more mass appeal? The two concepts that Rossignol picks out as being vast improvements over the WoW model are no levels (collecting skills, not level grinding, becomes the object) and money - not XP - would become the driving force in a game. There are some interesting thoughts, but lest you think it's an EVE love fest, he cautions:
What Eve doesn't do, of course, is create a world that is as compelling and immediate as World Of Warcraft. And this ties in to my final point.
You might respond to all this and say: "but levelling up gives us something to aim for, the skilling in Eve is so much more nebulous, so to speak. It's better to have quests and a magic horse at level 40 I can aim for. That is why WoW has some many millions of people playing it." This is correct, and it's another reason why the principles, rather than the execution, of Eve Online are worthy of copying. If you were to base your game on Eve you'd make skills, items, and equipment both aspiration-worthy and customisation-friendly. It's about presentation as much as mechanics .... One of Eve's failures is the obscurity of its aspirational targets - any game wanting wider appeal needs to present this more clearly.
It's a quick read & worth a read through, even if you're only tangentially interested in MMO game design.
World of EveCraft [Rock, Paper, Shotgun]