Armor hardly cost anything to us anyway and why would you need to move fast in it? The people who run around in armor are the first ones to kill to get my Ceth Gunship. So I don't think it would upset the balance.
If you have a reason in mind then please let me know? Please note that anyone can still choose Armor Enhance so if there was a balance issue, which I don't think is the case, then anyone can choose it anyway.
Hmmm, interesting. I wish I was a game/patch tester...