I Was told Armor Class is broken on this server

[Broot]

I leveled with my cleric friend extensively on my Shadowknight and I stacked AC pretty heavily. He said that my mitigation was worlds better than some other tanks that he was healing for when I was offline.
AC does help quite a bit - I think people tend not to notice because AC doesn't cause a flat reduction to damage like modern RPGs have leaned towards. So a super tanky tank can still get quadded for max damage. However, if you pay close attention, you will mitigate more through enemy misses / partial damages.