Wiki does say a lot of stuff that needs other campaigns.
But regardless of the skills from the other campaigns it is still
possible to beat the game with just Nightfall skills or else they
wouldn't have released it as it is now.
I suggest that you try to hook up with a group without henchmen or few
henchmen. I think that'll produce the best results.
The mission Gates of Madness was hard on me because the heroes just
don't have the necessary knowledge that a human player has to perform
well.