If they want to get lazy with encounter design, they could always tack on a glancing blows concept for special moves, so that you're still "evading," just not the whole hit. Ducking enough so that you take it on the arm instead of the face is a good idea even if it doesn't get you completely out of the way.

Leave auto-attacks all-or-nothing so there's still general spikiness and evasion. Then make special attacks glance a certain percentage at base. Maybe a random range, say 5-15%. Then let CDs increase that percentage. For example, Featherfoot on top of the tank stance would push your auto-attack evasion to 100%, and your special attack glancing percentage from 5-15% to 15-25% (or whatever). Other CDs can futz with the percentages in other ways and/or do something with self-healing.

Throw in a longish CD that guarantees special attacks miss, but leaves you flat-footed (no glancing, no dodging) for X seconds afterward as an answer to HG/Holmgang.