I think Org didn't think it through when he gave the right to choose a castle without a ban on certain creatures, which creates an imbalance.
P.S.
at least he could have given each player the opportunity to veto one castle.
Actually, it's a standard ban on creatures for each castle. ;)
But if you're sure that Necropolis is strong on this map without Gosh, I can try to prove the opposite somehow. ;)