I haven't had an issue like that with armor crush personally. It's added a lot of freedom in regards to dungeons and dealing with situation for me.

Also after playing with the aggro moves more the first move is a straight aggro reduction on a party member. Meaning it takes there aggro and dumps it immediately.

The second and more interesting aggro moves allows you to put the hate your ninjas accumulate on another target. This means if you pop it on tank, pull a mob ahead of the tank by attacking, there will aggro straight to the tank instead of you. This would be a good move for instance if you wanted to maximize uptime on dps on a golem in t9 as soon as you see them without waiting on the tank to take aggro or have the tank move to position x and you attack the enemy making them aggro on the tank and move to him.