Assuming Superbot releases more than 1 additional costume for each character, what would you like to see for some characters? Here are my picks:
Radec - Helghast Sniper, Winter Helghast
Ratchet - Alister Azimuth, Imfernox/Carbonox Armor
Kratos - God Armor (like he wears during his Lv 3), Dominus Armor
Kat and Sackboy have dozens of costumes, so that one's obvious.
Big Daddy: Subject Delta
Heihachi: Shirtless with the Blue/Gold Hakama from Tekken 3, 5 and 6 (this was his default look in Soul Calibur).
Nathan Drake: Doughnut Drake, maybe Heist Drake.