Couple of things that will make it look better.
The main body of the tank should not touch the ground 2-3 voxels is enough to get rid the squashed feeling.
The wheels should not be that smooth, try to not smoothen them that much.
Wider turret seems more fitting, not much wider just some.
You have faulty colors on the voxel, there is an menu in the voxel editor that will show you which areas that contains those Scripts-> colour schemes-> pal pack-> no unlit-> no unlightcolurs. The pink areas are the faulty colors.
Overall normals are either to smooth or not shaded well, try painting them manually instead (index 2 normals). Godwin has made an tutorial about how to paint the normals.
Keep the design it is not that wrong, it is just a couple of things that are off anyway
