Dark:
The thing about the build is that it doesn't really matter what equipment you use, the strength is in the synergies; you can pretty much go with whatever gear you want and be fine, though it is a slight bit more difficult for two-hand fighters since they lose the shield.
If you go with the IK set, you can leave dex at base and just work on str and vit. There are plenty of AR items like charms and rings and such in the game (not to mention the bonus to AR from set itself), and then Battle Cry cuts enemy defense in half, making them a lot easier to hit.
Long:
Confuse is AoE, and I'm pretty sure Mindblast is too (just a very small area on it, however). Thanks for pointing out the stat issue, I'll change that and update the page.
As for the run/walk question: speed is a very confusing statistic. For one, the amount gained from items works in diminishing returns, while that from skills doesn't, so we can't just add the totals together. There is a rather irritating formlua for all of it around here somewhere. Likewise, I believe the speed penalty from armor is applied at a different point in the equation, so that it has a much larger effect (it was either at the very end, after item/skill r/w had been calculated, or subtracted from the skill...I can't remember off hand).
In reality though, the main reason for not using something like sacred armor for enigma you've already mentioned: that contemptable str requirement. The big reason to use Enigma in general is because it lets you skimp on str in order to pump more vit, thus something like an archon or wyrmhide or such make great pieces to go with. My current rendition of the barb has 81 base str, which goes to 101 with annihilus, and then 131 with my BotD berserker, which lets me put on the archon, and then storm, and so on and so forth. Likewise, if you equipped Enigma using str items, then removed the str items, Enigma would turn red and dissapear from your character. I tried doing it the other day, as I was thinking about similar things as you, to no avail =/.
-Hal