Splorf says AC is not useless on enchanters:
http://www.project1999.com/forums/sh...d.php?p=798998
TLDR: AC does reduce melee damage taken, even for int casters. And with enchanters especially, who often have runes up, AC is even better in increasing the time it takes for them to go from normal to dead.
Imo but without the actual testing: agree with Splorf. AC probably causes mobs to miss more, which means I get pushed less, which means I tend to get off more spells without interruption. Bash probably misses more too, which obviously is going to let me get off more spells without interruption. And while AC doesn't help deal with spell damage (but +HP or +resists would), I bet 90+% of the damage *I* take playing a 60 chanter is melee damage.
Your results may differ depending on level, gear, whether you rock rune 5 and bedlam 24/7, what mobs you're fighting, etc.