Honestly I have to agree with Mamoru on this. Original thought almost completely died out a long time ago. Yes, obviously Microsoft is putting these in to place because of Mii's and Home. It makes good business sense, who cares if it's not original. It's either keep up or die out. Does is really matter who came up with what as long as we, the gamers, (no matter what console preference, if any), benefit? No, it doesn't.
Yes, it's an obvious rip-off, and yes, there is no way in hell that either Sony or Microsoft will credit Nintendo with the idea to incorporate avatars into the current generation -- who cares?
(Also, I want to stress that I'm not trying to be an ass. I understand where you're coming from, I just get very tired of seeing these sort of arguments being used as munition within the "console wars".)