No reason why Nintendo can't cooperate with the tournament scene to create a competitive matchmaking hopper like MLG in Halo 3/Reach, though.
Communities are nice and I support custom servers in general, but they're exclusionary by nature. I think it should really be a global feature available to all players.
Nintendo did have global communities for MK7, basically presets where everyone could go for various settings.
Would be nice if they had a global competitive matchmaking especially if they have real spectating this time. I don't really expect it but real time spectating on competitive matches would be really fun, especially if they keep the betting mechanic from Brawl and somehow make the coins worth something.