Well, it's not so much a matter of the genius dudes here, in the case of your typical closed-source windows-only game. Wine doesn't help here, because windows binaries are x86 binaries. Emulating x86 on ARM is not fast, so it won't work.

I expect a simplified client (lower graphics capabilities) could handily run on the N8x0. But the developers would have to port it or release the code, and they'd probably rather do neither. Look for MMOs that are open-source; I'd think there would be something out there...
And web-based ones, like Pardus, should work fine, but I'm the kind guy who'd rather find an RPG as a weapon in the game, rather than as a description of the game.