Dig it. Good paper choice. But didn't seem overly steamy by comparison. I thought you could have really push Vader's life support system in a big way to become some great mechanical, steam-emitting contraption reflecting his whole "anger leads to suffering" motif. Maybe even be run off magma originally gathered from Mustafar -- which seems like the kind of twistedly poetic thing Palpatine would do to keep him tortured and dark. (And that's why he'd have to recharge in that pod-thingy.) Anyway, you said you wanted feedback is all.
Love the design on Palpatine. The almost Prussian style robes and the Mask just add to his sinister quality. Kinda wish Dark Horse would commission you to do a Steampunk themed version of Visionaries or Infinities. So Epic!