I'm a rep 137 and I have been with this game since the beginning and have seen every rise and fall and meta there has ever been. I only say that because I imagine there are other players like me out there that have acquired every piece of armor for all of their favorite heroes but because of all the necessary changes and reworks a game like this goes through I still wouldn't say I have a main.
But I have realized the primary reason for that is because my favorite game mode is For Fashion! Once I make a hero sexy shortly after rep 8 because I will have unlocked all the armor options I cant help but start working on other characters.
A system i want to suggest you already have in place with weapons, but basically I would like to see rare armor pieces even if they are similar to ones we have just with added accessories or "flare" (to save dev time) and have the percentages raised based on how high your rep is.
This may seem like a luxury issue and not worth considering but ive heard many long time players say armor is a big reason why grinding rep feels so unrewarding and causes people to burn out easily. Hope this idea is passed to the devs, thanks!