To clarify things, do you want to unlock armor through a credit system, rank or achievements, just helmet and shoulder armor, a halo reach type armor customization, elite customization, ect.
I’m not totally sure about this subject, i did like halo 3’s armor customization because it was quick and easy, and it was a harder and funner challenge to get armor through achievements(ex:hayabusa). But then again the only reason i’m still playing reach is to earn credits to rank up to get cool armor. In halo 4 i do know that i want elite customization, a rank system like reach so you can rank up without live(cause i don’t have live) and possibly that you would have to earn a few achievements to unlock a certain helmet or body type. ex: you would have to earn the achievement “wakeupbuttercup” to recieve the pilot helmet in reach)