Find the maintainer of the relevant subsystem, talk to them via mail or IRC about what's bugging you and how to improve it, implement it, send a patch and it will most likely be accepted.

Where I have had difficulties getting something accepted is if your patch might cause problems later or doesn't solve the problem in a way that aligns with the vision of the maintainer. But while that might be annoying as a developer that wants a problem fixed now, I'd say that it's probably for the better of the whole kernel.