We're splitting hairs, but Frost at least has "bad" zoning options and her spin is relatively safe. B+2,2 is a phenomenal move, she's got great anti air game, and b,f+3 is one of the most annoying zoning tools in the game.
Kotal has no such things, just a whole lot of yolo. And a really useful command grab THAT THROWS THEM OUT OF THE FUCKING CORNER. None of Frost's BnBs (Except weird corner uppercut combos) switch sides and ruin her pressure.
Frost with hit box fixes would actually be a really solid character. Kotal will need frame and range buffs all over his movelist to even be functional.