Assuming 15x15 are even a thing, I think adding the option to generate them would be great. I've probably generated at least 200 maps over the last week alone and it's led to some interesting theories that I've had small talk with other players about.
For the most part, when you're doing a custom map using the sliders to adjust the settings, the map size and player count STRONGLY matter when it comes to how interesting the map will be. For instance, 6v6 on a 10x10 will lead to pretty boring maps most of the time. In fact it often feels like the sliders don't actually do anything. But if you 6v6 on a 20x20, the maps are suddenly much more varied.
The problem also appears with 4v4s and 10x10 maps. Try generating some, and you'll see most maps are pretty plain. Now lower it to 3v3 on 10x10 and the maps are suddenly much more interesting again.
So my theory is that the mapgen has some sort of soft-playercap for each size. I'm sure it's not programmed that way, but however the algorithm for generating the maps works, seems to work like that. You can get pretty interesting 4v4 and 5v5 maps on 20x20 as well, but lower it to 10x10 and they're mostly boring, open plain maps, maybe with a mountain in the middle.
So basically what I'm asking for is an intermediate between 10x10 and 20x20 because 10x10 can be too small, and 20x20 can be too large at times.
Is it even possible?