How to counter mind control spells (subjugation, blinding, etc.) used by a Necromancer?

Your so-called “proven” method is a trap for newbies. If you split up the Paladins you took instead of Isabel’s Knights, these two stacks won’t be worth blinding with Vampires and then finishing off. Besides, judging by everything, your Paladins won’t be doing much besides healing. Also, there are other suitable targets for the Berserker, such as Angels. And your Darkness vulnerability won’t give the Necromancer much of an advantage with high spell power. The only thing you can hope for is a cloak, which is hard to find.