I don't know guys, I've played Battlefield 3 MP quite much on the past few days. I decided not to let this annoyance to ruin my fun but to learn to recognize the uniforms. It's quite easy when you get the hang of it. All you have to remember is which side you are on, that's confusing sometimes. Choppers and Tanks are easy, Jets and some other vehicles hard. At first I played only on normal servers (no TK) but now I'm back playing my favourite, HC-mode. Being not able to see player icons is really quite of fun way to play, if one considers that as some sort of 'realistic'-mode. :)
Anyway, the multi-player friend/foe icons DO work! Or work in a sence of showing up when I'm spotting an enemy or aiming at friendlies for a while. Choppers and vehicles usually show up almost half the time. All the flag markers do work. So whatever their problem with the icons is, it cant be very difficult to fix. One thing I noticed was that the Icons are scaled wrong, 3-5times wider than usual. That tells me that they have not tested this game with multi-monitor setups before launch. Shame on you, Dice!
[EDIT] I'm not sure if it has anything to do with me seeing MP-icons half of the time, but I updated my nVidia drivers to 285.79 BETA on monday or so.
Also on the newest beta drivers and I noticed they do pop up more frequently but I went back to the rez fix because I just kick more ass that way. But I just played skyrim and went to BF3 for some Multiplayer and playing at that rez hurt a little.