When you kill someone it should say in the middle of the screen other than being in the text box on the left, and when you are aiming at someone it should say their name over their head.

Yes and No. Its not black ops we dont need to see their names. Yes having another way to see your kill would be nice.

I'd disagree to it being middle.. but along the bottom or top I wouldn't mind.
And as for player indicators, it shouldn't matter who it is at the tip of your barrel ;)

Was about to say it'd be useful for admin, but personally I'd prefer an entirely different admin 'class' separate to the 'blue' and 'green' teams that would auto be invisible, fly, teleport, move fast, see all player movements, kill/death logs etc.

Many people disable centered text because it blocks visibility. It could be an option if the hud gets updated.

Seeing enemys' names would make them easier to be spotted. I think it's a bad idea.