Something about how the motion trails form small points just seems inherently wrong to me. When I see motion trails like that, I think, ok, a sword shape would make that; very little movement from the base, a lot coming from the end, therefore forming a sort of pointed looking motion train. But the claw is so rounded, it's kind of tricky. I'm probably not making that much sense.
In any case, the motion trains from the closing ought to be diagonal somewhat, instead of horizontal. Unless the claw thrusts forward as it closes, which would be pretty damn cool.