To be fair to T10 you could at least change cars between races in a series, I thought that was a neat touch. And while I get where you and other fans are coming from, they'll never please everybody. Personally, I would love something like Project cars. But while PC2's career makes sense, having track day/road car races for each 'class' before the 'professional' ones would be amazing, and also the option to do historic stuff first and not having to unlock them.
I think I'm gonna miss PC's multiple liveries for cars, and while T10 did show a single-make race in the first trailer with different liveries I'm not sure they'll carry that across the game and some of the fan made 'goofy' liveries kill Forza for me at times. Putting a USAF livery on a Shelby Daytona should be a bannable offense lol