Its called squash and stretch. In animation you have a character go backwards before they go forwards, it adds impact to what they are doing.
For example before a character runs off scene they swing their arms back and they turn slightly to the opposite direction of where they are going.
Then BOOM the blast off.
It makes the action stronger.
As far as Martian Manhunter's forhead, I agree. But if they just give him a caveman brow that might work. But It is probably best if they don't.
and as for Batman, he is a human and there is very (to no) variations they can do to him other than his clothes or a possible costume. But he is also not a character that is definatly going to be on Smallville.
Martian Manhunter is, and he has the ability to change shape. Plus, his form in the comics poses a problem for the show. how do they show him and not make it look silly. (like Martian Manhunter in the horrible TV movie)
So I was wondering what you guys expected.