Unfortunately, I don't find survival games as fun these days. Like any game out there, there is a honeymoon phase with it. Everyone's honeymoon phase is different, some only have fun with it for a week, and then find that it gets boring, or some can play on for years.
For me, after I stopped playing for a month or so when I originally started my freshman year of college (September 2012) is around the time that I started to lose a large interest in SG in general (just the game mode). I attribute this to me overplaying the game so much during the summer before that, that the game became dull. I regain that spark here and there, but nowadays there isn't enough incentive to continue to play. The learning curve and the playing style is quite a bit different, making SG hard to be "just a casual game" where I can sit down and play a couple of matches a day and be happy with that. You can hardly make a dent in the leaderboards, again, without dedicating 6+ hours a day while consistently winning. And all in all, there is always a certain appeal that a game has when you just start playing it, hence the honeymoon phase.
I don't think its wrong for anyone to say whether they think MCSG is fun anymore, everyone's allowed to have an opinion. I do think that the servers do need to start planning out something that will give more incentive for your long time players, and even new ones, to continue playing.
Edit: Hackers, teams, and the likes will always be apart of this game, and nearly every other FFA type online multiplayer game. It always pisses us off to die to a team, but we ALL still team here and there. I wouldn't have ever became a part of this community in the way that I did had I never teamed with some of the people that I did back in May and June 2012.