Instead of TKL, I still like the idea of TKO meaning Ten-Key-Only. It is a tad wider, but retains 100% functionality, and perhaps adds extra. In order for touch-typing to work 100%, you ditch the middle section with the arrow keys and bring the numpad over such that the 0 is where the left arrow is. Then you make said 0 into two different keys. Numlock is turned into something that only controls output from this keyboard and not the system/OS state. That way when it is in one mode you have the standard inverse-t on both '0''s, '2', and '.'. And the standard nav block either on where numlock was through '9' (maybe ditch insert, or perhaps move numlock) or on '7'-'6'. Since you are targeting gamers with this board, the rest of this mode is where having that logic on-board helps: All the keys that are now doing nothing while the numpad is in Nav Mode could be fully programmable with other single keys or even macros. Gamers seem to like macros and this way you don't need to add extra keys to have them. Perhaps could even allow where insert and del and such are to be chosen by the user.
Then you can always switch to numpad mode and use it like a normal numpad. In either mode everything is basically where it should be while allowing extras.