This thread is for making suggestions of all kinds, and I'll start off with it.

Suggestions:

Bigger maps are always better, not only does it give more room to fight but it gives a better chance to test certain weapons with large explosion radius (I.E M9K Orbital Strike Marker, Surface to air missile etc.)

The sky is really not the best choice, as it's often used in a lot of full bright maps or poorly done maps. Gamebannana provides plenty of sky box textures for all your mapping needs.

Skybox textures [gamebanana.com]

A bigger mix of different kinds of fighting enviroments are always better. Not only does it give you more varity on where and when you can fight in one map, but it also lets you test what weapons work best for what enviroment. One section containing offices and another containing an open urban area literally make a huge difference and add more to the fun.

Scatter weapons and ammo throughout these maps. They're crucial for testing weapons, and not everyone wants to spam the N key to give themselves ammo all the time.

Explosive barrels and other enviromental hazards add to the fun and the challange, as it's always nice to see enimies flying into the air after a barrel explodes.

More secrets, secrets are always fun.

A saferoom is always a good idea, that way players have a chance to prep up and choose the weapons they need before they jump into battle against NPC's. Probably the best place to put ammo crates, health chargers and armor chargers alike.

That's all I have, just my 2 cents.