Well in my reminds about my warrior in Takhisis (actualy he got a leadership) don't remember exactly his name Heldar or something like this. I fighted with a lot of necromancer of Tower who had all the books and manual like veil of maggot, wall of thors (the most deadly s**t) and other crap like + 1 mummy specture and all.
Damn it was hard to kill them when I fight them the best stance was relax or defence + harden skin and sometimes I got sanctuare (but it had been dispelled in a first round) and if it's possible I was on mount...
And you know I won sometimes

I think if we remove dual wield we will get the same mummies as they were? or I'm wrong? if it is ... they would be fine.. indeed hard but still worthy and Heretic with a swords can take necromancer (if necromancer without mount and sanc) in one round.