Alright, Ill take looks on them and try to feel if something is needy.
Indy - I see future
It will look great i think, the road feels like a track that is used for long years.(it is a good thing)I say decorate the middle in that way too.Plus there is a critical road placement problem at the first turn, check the first curved part meeting with straight starting part.Or take a car and stick to the right side of track and go on topspeed, you will bump up there.
LSX - Nice lifting with the turns.The empty zone after second turn at right and left (the carpark) needs some environment.Plus after third turn, the little straight for fourth turn would love to be decorated a bit.
Stadium Cup - Yeah it looks nice, more of the spectator seats (whatever it is) till trees start in their line up would do it nice.Simple track, but looks nice.
Well i didnt go too deep, you wont need it.
They are all nice tracks, especially indy course.