First, the tracks should have diffrent sizes, or some way to stretch it.

I remember a mod on Gmod, where you select the wheels, and it would generate tracks on it, You could try to remake that system on here?
(I know i'm comparing this to another game, but its a idea)

Second, the tank tracks should have a Built-in suspension system, using a regular suspension helps, but not by much.

Third, The tracks noise is not to accurate, you could add a system, where you can hear the cranking of the wheels, like you do in real tanks.

Fourth (adding on to the first one) They tank tracks instead of being a whole, should be parts. If the track detects a track that is colliding with it, it will combine with that track.
The tracks will be in 3 pieces:
( would be the Back
_ would be the middle
) would be the front