Definitely not an easy one. I like to play solo with 3 characters, feels like it eases it up a bit and lets you be more "thematic" - dwarf can be a tank, mage a glass cannon, paladin/rogue support. When I played with 2 characters, that flavor was lost - both of them had to try and do everything instead of playing a more specific role.
This. Exactly my feelings.
Unfortunately, the difficulty with three heroes is much less.
So I am stuck in the middle with this game. I want the tension and win ratio of the two hero version, but the ability freedom, theme, and enjoyment of the three hero version.
For now, mechanistic enjoyment has won over mechanistic frustration - so 3 heroes it has been since.