Look out.... -boom- (headshot)
I told you to look out, but know, you got in my way, was going to shoot that splaser....
I think red team was one of the two choices because if(in RL) you'd bleed it wouldn't look like they were bleeding, thus giving your enemy the thought that your invincible and a rally point for your allies, which is what has been done many times in the past.
Now,Customizable armor is fun, and I'd actually like to see my custom armor color in Team Slayer, mine is brown so that way, when Im in a free for all, I can hide in the rocks with the sniper rifle and blend in. :D