I don't know how well turning the taunt skill itself into an aura would work, because, as it is, enemies are allowed to move. They're just forced to focus their attacks on you. An enemy could very easily just walk out of your 'aura' radius and return to ignoring you. With the current AI, I know they would definitely do that, too.
Taunt should remain the same, just bypass armor. A talent should be added that's pretty much reverse-Stench, in that enemies are more likely to attack you regardless of where you're standing (but that doesn't mean they'll do stupid shit just to hit you - but if they're ranged and have the option between you and someone else, it should pick you most of the time, and a melee will opt to use less AP to actually hit something that turn, if you're closer, than spending literally all of their AP to change the glass cannon, only to not attack at all).
I would also be fine with a talent that just improves the chance of whoever you target, to target you. That way opportunity attacks, retaliation, etc, give a small.. 'aggro' gain, for lack of a better word.
