It's just been denied a million times. Subconscious takin care of ya :P
Personally,
+1 on the idea. Love to be able to have at least an equalizer for the cits.
As for the argument it will take away donations, think of it this way.
>Player plays kitpvp
>becomes more dedicated, leveling up kits
>Enjoys the server, is now loyal to it
>Explores other parts of the server
>Donates for perks in other areas and love of the server
Or, they still can donate to shave some time off of leveling up.