I had a thought as to the mecha line of skins and how I think kalista could be a perfect fit for it.
Also an awesome bot lane ive been playing for a bit now is 
/ 
. The ult combo is real for lane and perfect for team fights. The skin combo would make it complete
Eh; I don't think it's a bad idea, but at the same time there's probably a better skin concept for her next skin. And she's a bit too human for a Mecha Skin, in my opinion (Aatrox is at least very demonic with very distinct wings for his sillouette).
Not to mention she's new enough of a champion that she doesn't really need a new skin anytime soon, at least not before Zac, or Jinx, or Zac, or Vel'Koz, or Zac (There's a pattern here).
