Most people I know don't like waiting through a server to death-match since it takes so long for the players to find each other. I'd like to suggest that if there isn't a kill after ten minutes or so, something spawns like a few mobs near a player like the Gamemakers would in the Hunger Games book series. Another thing would be to teleport two players together that are far away from each other, perhaps in a certain area that isn't adjacent to the other tributes, so they would be forced to fight each other. Again, this is like the book series, when they pushed tributes closer together to each other using obstacles, fire, etc.
Another suggestion I have would be to shorten the lobby time. Some people just want a short match to kill the time, etc. If this doesn't work, you could also allow players to vote to skip right to the setting up of the game. If more than half of the server votes, it would send you straight to the map and put everyone on their pedestals immediately.
Lastly, I would probably fix the sprint-before-countdown glitch. If you didn't know, at about two or one second left before the games begin, people can sprint towards the cornucopia and it won't push them back. I have to admit, I do this every so often, but it can give an unfair advantage to people who don't know about it, are new to MCSG, etc.
That's all that I have, and I hope it's good enough