As far as I can see the difficulty level doesn't matter.
I tried defeating some Orcs that were my level with an Orc Sage that was 2 levels higher, playing on Normal.The Sage kept on charming one or two of my characters, ultimately defeating me.
I tried again on Easy and the Sage still charmed and I still lost.
My point is, if that Org Sage is pre-loaded with the same spells on every level, like Charm, what does it matter what level your playing? The same enemies that can heal their allies still heal their allies. The bowmen with fire arrows sill fire those fire arrows at you. What level you are playing at seems to make no difference.
