Number of players can be set to whatever someone deems necessary. Some servers run upwards of about 60, I personally believe 30-40 is plenty. Current size of the map is tiny compared to what the main island will be in the future. As far as bugs, the game is in beta and Wasteland is a gamemode being ported over from ArmA2. As the game gets it's updates, so will the gamemode and eventually most, if not all, bugs will get ironed out.