Blessed aim isn't necessary. You can increase the proc rate by increasing the attack speed.
I don't really see your point there.
I mean, choosing Blessed Aim as the built-in aura doesn't mean a sacrifice in attack speed.
You can very well have both, to increase the proc rate even further.
eth mania armor
Isn't Mania a weapon runeword?
On act bosses, you cast taunt.
I guess you meant Battle Cry, cause Taunt doesn't work on bosses.
I've went that road in the past, it hurts the DPS compared to Blessed Aim + damaging curse, though it's probably great for HC.