Straight to the point.
As with all games from outer regions there is one huge flaw when they get imported-

Localization of material and content.

What do you think would be the localized content we receive. Let's face it, Miku, Fate Night, and so on wouldn't live too well with the general populace, especially when competition steps in (WoW, RS, Guild Wars, Deadmau5). We'd probably get Indiana Jones, Star Wars and other cameos that are more western instead of the ones we liked on JP.

And yes i know i said RS, with sega's track record some games could still trample on them effortlessly they don't got the best MMO history.