I think there should be more of them which are of a decent quality for multiplayer.
The only games that I've played that I think has really good integration of avatars would be Bomberman Battlefest, Dorito's Crash Course and Full House Poker.
(That's from the top of my head)
I know there are lots of indie games but it would cool to have some more ARCADE and full retail games which have achievements with avatar awards too :)
A proper ARCADE kart game, 3rd person shooter and RPG that has use of your own avatar's would be cool I think.
Apologies if I just sound like a fussy banana.