The reason why Sasuke got so many outfit changes is because Kishi has some difficulties drawing him. Choji is Kishi's favorite character. Sasuke is his favorite one to draw.
I think that Kishi is really showing that Sasuke constantly changes his allegiances and ideas (first he was loyal to Konoha then he went to Orochimaru's place, then to Akatsuki), whereas Naruto is still the same dude with the same friends (though he has made more) and same ideas.