Well, if it will support easy modding, and installing unlimited cars and tracks by drag n'drop, also if it supports dynamic day cycle and weather, on top of RBR-esque (or better NGP) physics, it's worth looking into personally for me... They have daytime cycle working, i wonder does it affect track grip too? If so, it'll be neat having 20+km stages where you can feel the change in lighting and grip over the stage. Especially if they manage to make dynamic icing on some tracks like Monte Carlo where it can be dry/wet tarmac daytime and fresh ice in the evening... But that's just my personal wish of what i'd improve over RBR, and can not correlate with this title...
I have a lot of doubts in this currently too.