if you see a guy walking down the street dressed like a cop do you assume hes a cop or do you assume that he just found a uniform lying around and decided to put it on. frankly that was one of the best improvements in the game since it lets you sneak into an area that normally you would get shot up in.
better yet, make it so that whenever you get within a certain distance (and perhaps facing) from a faction member of the disguise you're wearing, your chances of a successful disguise are determined by you charisma/speech/luck.
the way it is now, everyone's a master of disguise
I'd rather do less modification on my own end and rather have someone just tell me what to do so I can spend more time enjoying running around in NCR Ranger Combat Armor. Nothing personal, just wanting to enjoy the awesome armor without being aligned to a faction with risks of consequences.