I'm currently playing FM7 and it's pretty refreshing after decades of Gran Turismo.

Everything I heard about the upcoming reboot sounds very exciting to me. The most outstanding changes are probably the physics. In FM7 physics run at 60Hz with one point of contact per tire and a few factors that determine the grip (surface, angle, tire temperature & width). In the new FM physics will run at 360Hz with four points of contact per tire and even more factors that determine the behavior of tires.

What I hope for is a more refined singleplayer campaign. Best case would be separate campaigns - for each car division individually. In FM7 the campaign was too rich in variety imo - basically for every small cup of 4-6 races you had to pick a different car. I would love to see a more streamlined singleplayer experience with more coherent progression.