I would totally volunteer to be a GM who's only power is the ability to ban hackers (and maybe instant teleportation to make that easier) and nothing else. But Nexon wouldn't have it.
Probably because it's dumb to be handing out GM accounts to randoms over the internet. Who's only power is to ban hackers? What, does banning require them to enter some intricate proof for the ban button to activate? lol.
Use your head. Anyone can say they want to ban hackers, then go around and ban half the server because 'Herp derp Nexon trusted some stranger over the internet'. I mean, just look at Tespia/Private Tester selections and how some folks had concerns that there could be picks who held ill-intentions and may take advantage of their position to find exploits or other **** to abuse once content reaches the live server.
This is coming from someone who's account dates back to 2006. Your suggestion of volunteer in-game GM is terrible.