Yes i agree, maybe a pink/green shadow will help more.
Hmmm, maybe if the armor is more like the animal and less like an armor would help, maybe changing the helmet too? since it will be the first part the players will look (because is the bigger part)
something like this for the feet, making it more claws. (Shitty fast edit, sorry, im not an expert in your way to sprite XD)

Mostly i think the basic problem of the last armor is the fact is just a recolor with wings, so doesn't not give the feel of "YEAH POWERUP"