#1, make it look stealthy and stylish, with the armor plates at strategic positions to allow for the most flexibility
#2, make it cause you to not get blood splatters when you get hit, until you're low health.
#3, Make it dyeable, and let us choose what color combos we want instead of random ones you pick.
#4, failing the first two, make SURE that #3 is in.
I was watching an interview with Alexandre about getting narrative rewards that actually affect your gameplay experience, and the super-armors being treated like a skin instead of a normal armor piece takes away the enjoyment of them. The armor of Brutus didn't even have animations for the poison-blade, and it didn't have a hidden gun on its bracer. Remember to make it actually seem like a legitemate upgrade, and don't let the normal armors you get from buying them be as strong as them.