I don't think we will ever see the big maps again. With the caps on the arenas they won't let the caps get high enough to populate them. They where trying a few things to try and control which bases were capturable at a given time to avoid the "land grab" of bases that couldn't be protected due to the lower numbers, but most people avoided the arena with those set-ups in it so they never got it to work well for lack of testers.
So we are stuck with the few maps we have. Of all the maps that they have had in AH, I think most of them have been made by customers. I think HTC did the first few, and the beta, but I think the rest were done by customers.
I wish I had the time to put into building maps.