I had a good idea for a map layout today, but I'm too lazy and busy to put any effort into learning to map.
Basically, my idea is to take ATCS and duplicate it nad mirror the duplicate, as if you put a giant mirror next to it. Sorry if that's confusing. Then join the two hallways, and open the conjoined section of the hallway up to the outside. Then perhaps remove the hurtful blue walls from this center portion. Of course, you're not building an ATCS map, but I figured you could use an idea. Fell free to mess with it and stuff.