Naruto is just so bad that it's terrible. Berserk is worth roleplaying in my opinion because of the beautiful dark fantasy world that it's set in. Inuyasha is indeed somewhat interesting (my sister's obsessed so you can't help but hear of some of the backround stuff) but when it comes to feudal Japanese RP, it's the politics of the clans and of the Samurai that gets this boys blood pumping.
Oh and Full Metal Alchemist isn't bad because it is also rather dark. And dark RPs normally attract more capable RPers in my opinion because I notice many whom wouldn't mind jumping in with a happy world with cuddly critters and what not, but few that'd like a world with people like... turning their children into beasts that then later find themselves slain.
As for Naruto, its more a Mix of Inuyasha and FMA... It happens in its own little world, but the few nations there are are ruled by fudeal lords with the same set up as old Japan... it just so happens that most nations also have a hidden village of ninja in them that they contract out on missions.