I think size was a huge reason maynard won, as claudale says they were good at the same thing (edge to maynard) but maynard was bigger.
Size will hurt edgar in that he will struggle to take penn down. On the feet he is at a talent disadvantage.
Of course edgar has a chance (some have stated 1 percent if penn doesnt train) so yes there is serra or buster douglas type hope. But when evaluating the fight i dont see any real advantage for him.