FPS on my system was very solid. I like the placement of weapons. I think you should add in a few health vials maybe in a long open corridor or other wide open space. The health pickups were out of the way most times, but not any moreso than what they are in some stock maps.
Also, in each team's base there's a bunch of windows at one side. The lowest vertical window appears to use a texture that looks like it's getting rained on while the other windows do not display this. Consider removing the rain look or adding rain wash on all the windows plus some falling in areas open to the sky.