Remove/Replace Fortification.

[Vhlad]

It's been demonstrated that it is possible a large amount of builds to have decent Armor Class, simply by trying. See my exchange with Vhlad, where I showed him that his ranger wasn't even 20 points away from an equally buffed S&B character.

No Borror0, you're wrong. For reference, http://my.ddo.com/character/thelanis/vhlader/

You're looking at a 20 ranger with:
14 base dex
+2 dex tome
+3 dex ranger enhancements
+6 dex item
+2 exceptional dex TOD ring
+1 profane dex litany of the dead
// 28 dex for +9 bonus

DT leather armor grinded out with dodge +3
+1 alchemical armor
+2 max dex bonus from dwarven armor mastery II enhancements
// +12 AC from body slot

+5 deflection // helm slot
+4 insight // weapon slot
+2 dodge // bracers slot

+4 shield tempest III enhancement
+1 dodge feat
+1 two weapon defense feat

+5 natural // 20 ranger barkskin
+1 dodge // 30 second haste potion

54 self-buffed AC for a pure class ranger with substantial investment in AC, taking up many enhancement points, feats, and 7 item slots, with heavy investment in raid and crafted gear.

How exactly does requiring every class to slot for AC increase diversity?

This ranger, with some of the best gear available, is sitting at 54AC. And you want to tie heavy fort to AC when mobs in epic desert treat 80AC like it's nothing? Or when other builds (such as monk splashes) can reach 100AC? What the hell is a pure class THF kotc/hotd paladin, THF kensai, warchanter, barbarian, wizard, sorc, cleric, favored soul who cannot even reach the 54 AC of my ranger supposed to do? What is a new player without these items supposed to do?