Commander should not need heavy tanks to be good.
Actually Commanders with heavy tanks should have weaker abilities so they become less dominant.
As for skill shot I guess one could add a couple of shot that actually truck targets so that they can deliver some consistent damage.
I actually agree with this, particularly the commander with heavy tank should be balanced with weaker abilities -- though we're in so deep that it'd need to be a total overhaul or not, since just changing a few commanders here and there would effectively kill them until they are all equal.
Though, quite ironically, Wehr just got a commander with early infantry + premium medium + heavy tank that while not a call-in can be rushed.