I think one thing that is good to note is that idea of the mecha have more than 2 arms and 2 legs. To some people this seems odd and unrealistic.
Limbs converted to treads/tires on the other hand would make sloped traversal and rocky terrain problematic. May as well make hover mechs instead.
Side Note: I really like this mech Grummz posted. Reminds me of the early Hawken days. But this mech doesn't really line up with the pilot forming the underlying skeleton of the mech like the light and medium does.