My PvP thoughts:
Balance - There are buy zones and everything costs a money.
Small - á la Counter-Strike
Medium - light vehicles are very expensive
Big - classical ArmA
Last hope (aka Conter-Strike) - There is a T team and CT team. Each round T tries to plant a bomb on one of several spots on the map to destroy the objective. The CT team has to prevent bomb explosion.
Capture the flag - There are 2 teams with flag in base. The goal is to take enemy flag and take it to your flag in your base to gather up score. Your flag must not be taken. Player respawn in base or near the middle if their flag is stolen.
Key hunt - There are 2 or more teams and one player of each team holds a key. The goal is to collect the keys of the other teams and gather up the score. Keys emit radio signal. Players respawn in base.
Victory is achieved by points or time-limit. Realism should stay. These game types probably doesn't make sense IRL.
@metalcraze: No. I'll not go play it in BF3 because I want bullet drop... You said that BIS has monopoly. Well maybe it's time to take it further...