I thought of some little changes like ammo boxes in the middle, located between the spawning room and the challenge room. It is a good place to camp for shooting zeds when they can't kill you and it's annoying to always go to the back, use the trader for full ammo, and then go back to the middle.
I do not expect this to be done in less than a day, you probably don't read this at the moment I post this and I don't know how long it is to edit and upload a newer version of a map, just thought it would be a fun addition.