Gonna throw my 2c in, though each of these have been mentioned before.
First up is money. This is the biggest flaw imo. How in the name of God am I supposed to get 1,5 millions to buy 1 car after spending everything after doing all the championships? Then let's think about the achievement/trophy "God of cars". Own every purchasable car.
...
Just how am I supposed to make millions after millions to get all of the cars, there are so many ones that cost over a million and it's almost impossible, I guess the only way would be the casino but I don't own it and that is definitely a problem lol.
Photomode. Lack of real importing system like in most modern racers makes the photomode pretty much useless unless you wanna spend some time importing your pics from the HDD. It's also missing the "focal lenght" option that is pretty important if you wanna take good pictures. For example, the great photomode drags me back to NFS Hot Pursuit again and again and atm I have over 300 photos on my laptop. Yes, I am a photomode addict :lol:
Buggy online. I know (at least some of) this is gonna get fixed when (if) the patch comes out but it's really annoying that when every single one of your friends is playing lol of duty and when you finally get one to play TDU2 with you, he quits soon because the servers aren't working properly >_>