I am for the idea of using real faction names as long as that faction's members agree. There is one change that I would like to see.
What if there was a way that Gree could categorize all of the factions out there and split them up into a 3 tier hierarchy. And then use the best faction of each of those 3 tiers. Or choose the best 2 of each tier. The difficulty would come in where Gree would have to choose what the tiers would be based off of. The easiest choice would be to use WD placings.