They should add a system that kicks people who have been afk for a certain amount of minutes so as to avoid the giant build up of afk zombies and humans at spawn (Sometimes the alpha zombie itself). Yes, many people love farming the zombies that are afk at spawn but that is not the way the game should be played, with a focus being on the actual combat between zombies and humans. Some of these afks are also afk simply to get on the 'most games played' or 'most times played' leaderboard which isnt a real representation of their 'dedication' to the server and is just a cheap way of getting your name in the lobby. (It's also really annoying when they get stuck in eachother and an afk person stops the real final person from being able to win and get a level) All in all I suggest a 2 round (10 minute) timer that kicks them to the lobby if they havent moved so as to avoid the problem of afks at the spawn and filling up the server - I have been on games where 75% of the players online were afk.
Support, It gets really annoying there is AFK Humans inside of AFK zombies at the spawnpoint so it would be harder for zombies to win. If this suggestion gets accepted, some people might use a client to make AFK people move.