In my opinion, there are enough maps. With more maps, theres a smaller chance of my favorite maps to appear. I think 1 or 2 extra maps per seasonal event is more than enough extra... I mean, if theres new maps being created right now, I'm okay with that, but I dont really see any desperate need of adding new maps.
They could do something like rotating the maps around, so every month theres some new maps... but that might have 2 disadvantages... 1: A map loved by a lot of players might disappear, and 2: it will take a lot of extra time to create new maps...