Its been talked about before on one of the Goliath threads (not sure which one) and I think they said you cannot present a new hero but Im not sure on that one.
Interesting...I wasn't able to find that thread on search... would like one of the bigwigs to weigh in on this...seems wrong because Goliath text says, "
opponent may present" so it's by definition not Goliath but the
opponent that's presenting the hero...anyway if you're right this nearly breaks the game because it turns Goliath into a non-negatable autoblock against every hero except for a small handful of OT giant-slayers (which are now going to have to be in pretty much every deck).
I can't imagine that this was the intent when the card was created... wasn't this issue of Goliath & Wall of Protection playtested and vetted out?