I Think about this:
Team Kill Punishment:Hacks enter on the server constantly, and all make TK, i think an punishment for tk is good like: be Jailed for 5 minutes or if you do TK 3 times you is kicked.
Beer: Add One more item for your inventory, this is the beer or the Vine, you drink it, restore your hp, but you gonna keep drunk, for example: your screen gonna move in Different Directions, When you walk after drink it a lot you gonna walk like animation /drunk
Sniper: in the top from some Buildings, you can find a sniper.
Radio: in-game you dont have a radio, so you need to find one, you can find one at 24/7, ammu nation or U.C / S.T.A.R.S base.
Bases on Top from some Buildings: Up Some Buildings, you can find bases, they are not safe, Here have some tables, radios, computers... and here you can make contact with S.T.A.R.S or U.C by radio.
Mines: One human can make /placemine to place one mine on ground, so if someone touch on this mine, it explode and kill in the time, but you need to find it at 24/7 (Good for make Strategy and defend yourself)
*Idea taken from another Server*
Police Trucks and Cars Blocking the Road: in the roads, you can find Trucks and Cars from the Police blocking the Road. (It is good to be used with my idea "Killed Bots" those bots killed are cops, near the trucks and cars).
I Hope like my ideas