Our current GvG arenas aren't that fun anymore. If we had something worth protecting then it gets people into it. I haven't seen many GvG matches lately.
The randomizing could work, it can be like making a reservation where everyone can join, not just guild members. Teams can be on a shadow/dark type harkon or a regular rainbow/light type harkon. To make it more creative, different harkon colors with 2-4 teams.