My suggestion for maps would be following:
Story maps: No changes.
First portal: Let him deal twice the dmg and double the hp. Runs take longer and dps will die like flies in redzone
Second portal: No changes.
Third portal: Keep the damage, increase hp by 5x so the run takes longer, let warriors go down to 10%hp only (as in orrick) and keep other classes get 1hits. Increase gold loot only in this map by 1.5x.

1st and 3rd maps are too easy and should require wars.