The size of the Kinesis Advantage is another big problem in gaming I reckon, with very little space left for the mouse - I have a full keyboard with numpad and I'm already thinking of going tenkeyless for more space.
EDIT: ah... nevermind, these comments have convinced me to splurge on a Moonlander, which can be used with only the left half plugged in. Also probably a good idea to invest in an ergonomic setup now that I was thinking of removing evil and going back to the Emacs keybindings.