Super Galaxy Gnar !!!
Not so sure about the theme or lore which could end up with a prehistoric yordle in space, but the sole idea of mini Gnar getting into a Mega Gnar shaped mecha when he hits full rage makes it worth it imo.
The animation would be the mecha appearing from behind with the front open and mini Gnar jumps into it, closes mid air and roars (similar to Super Galaxy Fizz getting into his shark-sub in his recall but much faster).
What do you guys think, is it worth it?