Well, you can always limit yourself (assuming you're a dev) with what you're allowed to do
Orebfuscator is a pretty nice solution to X-ray. As for super fast mining tools, you can just not add any to the game.
I don't think there is a limit on how many "block mined" you can send to the server per second. Or they might have fixed that. Some cheats allow(ed) you to fly around while at the same time mining everything around you.
I think plugins like NoCheatPlus did something about it, but with more and more conservative cheat detection methods you start running into the edge cases of legitimate users.