I think that the coloration helps new players to find out at which team they are, even if there are some other things implemented, which will help him here. But it is also interesting for new players to know, what weapon they are holding, which cant work if any weapon looks like a toy because of colors. I can only agree that coloration is not needed for deathmatch, but in teamgames it is useful right now.
Very tough spot, because this discussion is break even for pro and contra. Always bad to get the best final result. My only good idea would be, make the weapons without colors but add therefor a small teamoverlay somewhere on the screen (maybe top right). Let the new timer (bottom left) be in your teamcolor. Just add some other "hints" at which team you are at when weaponcolors will be removed. Maybe use [GF]HarryButt idea ... I guess I am the last one to ask if it is about effects/eyecandy visuals

(I only watch high and nice effects when I look up some demos at times, never play on that settings)