Well, if you are hellbent on replacing the saw, might as well slot in a Gauss Rifle.
Still, the saw is kinda part of the striking visuals.
It's kinda odd they didn't manage to build a proper military version, I mean there are Vibroblades that size.
Edit: If you want to keep the visuals, you could actually replace the Saw with a large Vibroblade stylized after a dual-bladed claw. It might be a bit less prolific at chopping wood, however.