I think the flex in it should be useful when fighting spinners, absorbing their energy and not allowing them to get to the wheels.
Have you tried using a basic hinge set up... when the whole arm goes up, the claw stays stationary and grips the opponent. Simple and lightweight.
I've put a lot of time into the design for Nyx in the last week or so. Here's the latest chassis setup with 4 of the possible attachments shown-(Image removed from quote.)
^WINNAR^ I love how you've set it up to accomodate different weapons for different opponents- From what I can see, there's a battering ram, a lifting scoop, a vertical spinner, and a lifting spike (reminds me of Invertabrat from Robot Wars Series 3, actually), am I correct?