The biggest problem by far is the multiplayer system. It's the same old TDU1 crap, with the same problems.
You enter a race with 8 players, and the game just sits at the start line stating "Waiting for players 3/8" I hope they find out how to fix this.
But I'm really impressed with the physics system. The narrow roads and tight bends create a lot of equality. I whipped the ass of a few Ford GT's and Ferrari's with my Lancia Delta, just because they had to slow down way too much for the corners.