I agree with Eth on all of his points.
ZM is a drastically different playing style than GG, where cooperative play is only there because you can't shoot your teammates to go up in level, rounds are faster and there's no element of modifying the map for your advantage (making barricades).
So, it also takes a lot more moderation. Where you might need to worry about TKing on GG, it is mostly solved by the retribution system or a script that kicks anyone with kills below a certain amount. On ZM, people can't outright kill you but they can still get you killed and there's no way to have an automated retribution system as a deterrent.
Because of this, ZM needs admins to keep the peace, but recently they've caused more frustration than relieved.
I should say I'm surprised to see Eth respond and it's sad to see Eth wander off again. He doesn't often talk much in the game, much less on the forums. The last time he did wander off, I wasn't far behind because of a new wave of admins causing troubles. Most of those admins are gone with two exceptions, and those exceptions have set a precedent on the server that I feel needs to be stopped.
Also should note the upward trend on the stats might be a result of the tinkering you did a few weeks back, Zero. I made it up to the top10 recently in only a week and a half when it took me four months the last time if I recall.
And of course while I'm typing this, Vlad offers yet another wise post.