It was changed because there is no practical way to create enough 2D portraits to accurately represent the available combinations with customization of 3D models.
This. It's not that difficult to understand. Last game people complained that while you could customize your character's appearance any way you liked, the portrait - the thing which you'll be seeing constantly throughout the entire game - almost NEVER matched the actual appearance you created.
So sorry, but frankly I don't think the new portraits look bad enough to complain about. You are of course free to complain about it, but I just wanted to add a dissenting voice.
