I think it's the eyes - they're rounder and friendlier in your current avatar. Also, the chestpiece seems abnormally straight.

His cheeks look fat

Yeah, I'm gonna have to agree with GSR there. The way the eyes are slanted makes them look a little...off in comparison to your old one.

The cheek slit area thingies are too far apart and curved slightly outwards at the bottom. Making the edges of the inner cheeks parellel might fix it. That's my opinion.

it's too Chibi D:

Thanks for the feedback guys, I'll look into all those points.