My interest is more for MMOs, but my suggestions wouldn't make this much bigger - definitely more flexible though.
Your keys are based on WASD for movement, but with that configuration your pinky doesn't have much to do. One popular way to get more easily-accessible keys is to base them on ESDF instead, and getting access to more keys to the left of the movement keys. I'd also want both turning (S/F) and strafing (W/R) keys if I were designing something for my own use. I also see that you removed the 1-5 keys along the top, those would be a requirement for MMO use.
The other thing is around the thumb keys - space for jump, yes, but I'd like two or even three modifier keys there for MMO usage - that way you can maximize your accessible bindings without having to move your hand around.
I know your focus is FPS, so this stuff may not interest you.
AP