Evaluate my Vader please, mod suggestions?

If you're using him in raids and outside arena then yes, extra damage is great. In arena, as we unfortunately know, 97.2% of the time, speed is king. A speed x4 set with the remaining two being whatever mods have your highest secondaries regardless of speed. Ideally they'd be a pair, but Vader typically needs to go first under zPalp.

I have a second set of mods for my Vader for when I max out Wampa so I can run a high damage Wampanader team. Just swap between the two depending on where I'm using him. (Not my arena team)