I'm not crazy about Zatanna's new look, and don't particularly care for the child like models on Cyborg or Starfire. The outfit on starfire is better though. Raven is ok too I guess. Not recalling any other changed models at the moment. Doesn't impact game play, so whatever I guess. Just my opinion drop in the sea.
The game's look is moving from a comic book brought into game 3D look (albeit from ten years ago) to a real life brought into a 3D cartoon look. There are also differences in artist styles. Corum Rath (with his helmet) and Cyborg look really good and have lots of detail, while new Nightwing looks like he's made of Play-Doh.