The problem of not being able to differ friend from foe in wars unless you mouse over can turn out to be rather annoying - especially if there are like 4 or 5 reapers in the Arena, some of them friend others foe.
In my oppinion, the ordinary white text as it is now on mouse over might turn out to be not the best solution for graphical reasons.
Considering there is an upgrade planned containing a guild interface, it might turn out to be a good idea that each guild may create an unique icon their members proudly wear. (One needs to think about the requirements to craft such an icon: 20 Arena wins and 1000 Crystal Yaw or something the like.) This way one would easily see the faction each competitor in the Arena belongs to, making it easily possible to differ between friend and foe. There would be no need for white, ugly, large texts above each player but a stylish symbol matching the games design and the desire of the guild.
Kindest regards
Aerith