Well of course you could do both, I was just stating a reason why the uniform color thing would be useful instead of simply color-coding the name/adding an icon.

Thinking about it more, if every class got its own uniform for PVP it would make it a lot easier to pick out specific targets out of a crowd so you can better coordinate who to focus on. For example, a group of mages you want to take out the healer, but if the CNJ gear looks much different from THM gear it would be much more intuitive. Team Fortress 2's design discussions mentioned each character type having its own unique silhouette so you could quickly and easily tell who you were looking at, even in the heat of a fight.