A point I just made in a different thread was - if a level 12 party can deal with a bus load of gods then what would be a challenge for a level 12+ party?
Either the gods were weaker than they should be or the players skills / spells are stronger.
I accidently summoned a Water Elemental with a level 6 slot on Jaheira instead of a level 5 slot, and that thing is stronger than most of the mobs in the games.