I don't think we need another ability just yet, I'd much rather that fix the issues that currently plague mch. Like say... the AQ, why the heck does it take 6 seconds for it to start getting to work? Also, the other AQ button that makes AQ does its finisher is absolutely useless, because AQ would still do the finisher at the end of its timer. Enough ranting..
Anyways the grapple seems quite cool, I guess it could be similar to how akshan in LoL. Where it'll grapple onto a wall and circle it while doing dmg, can be released at anytime to reposition yourself.