I tend to keep a regular, non-magic weapon in one of each tank's weapon slots, in addition to to usual magical arsenal. So, when a mage thinks he's smart, and casts protection from magical weapons, we switch, and tear through him like he's wet toilet paper.
Please note that trying this tactic against a lich WILL get your ass handed to you in a trash bag.
I've no solution to the lich problem. I'll admit it, the thought of going without a mage boggles me. I tend to have two when I can. They're my artillery pieces, or, as I like to call them, 'meat tenderizers.'
So, if you're going without arcane backup, you've more cajones then li'l old me.