can you ad more wheons like knife rpg banana gun crosbow.......
Probably not. I like the balance right now. There's a gun for short range, medium, and long range, and they are all viable guns to pick from. You aren't at a disadvantage or advantage using any of them if you know how to use them correctly. Adding more guns would offset the balance and be a lot of work to maintain.
The other guns are perfectly as good. The sniper has little ammo and a long time between shots, which is plenty of time to kill them with the rifle or shotgun. Being good at using a sniper means you have to have excellent aim and reaction time, or you'll miss your first shot and die. It's balanced as it is.