The cheat menu is extremely simple to navigate as it currently is.
Also, since you talk about preservation; It's MAME's job or duty to present the user with the exact same experience as that same person walking up to a real cab with real hardware (which is does to the best of it's ability), so we should be happy there's even cheats at all.
Besides that some games have shitloads of cheats so how would one differentiate what's auto enabled and what is not?