In case anyone missed it and is working on stuff this morning, Swen and another, QA-related, dev made some comments in the General forum a few hours ago.
http://www.larian.com/forums/ubbthreads.php?ubb=showflat&Number=546776Summary:
80% is intentional, but should have been a soft cap, not a hard cap, with higher resistances provided by Zombie, potions, spells etc.
Hotfix will be deployed later today fixing the hitpoints issue and the 80% hard cap issue.