Why not have rare loot spawning on zombies too,so you can be on any server killing zombies knowing that there is a chance of rare loot on them.... the military zombies having a rare chance of finding military weapons etc? make them harder to kill or have them hit harder than other zombies.. problem solved.. people like group fights too.. maybe super zombies (rare) maybe 1 or 2 across the map that take more than 1 or 2 people to kill.. this will force team work