I just noticed that if two people pick Jax in his secondary outfit one has the gun on his back to tell the difference. At first I thought it was scrapped altogether.
I do have issues with the lack of color difference though. I mean it's pretty much impossible to tell who's who during a Reptile mirror match if both players pick the same costume. I remember watching grand finals from a tourney in Brazil and both players were playing as Sonya in her primary costume. Half of the time I couldn't tell who's hitting who...