I susspect allot of time and energy went into the WW1 arena but sadly in the end it does not involve many people.
Lots of people like a good tank battle but being bombed can be a pain. For very little time and effort a gv only arena could be set up I would think.
A gv only arena might be popular given the popularity of "World of Tanks" and it seems worth a try for maybe a trial period to see what effect it has on the game and how popular it is. I imagine it would be a different dynamic and that in itself would be interesting at least for a time.