Currently the helicopters are rather dull. They just sit there and shoot at what they see. For starters, I feel that they should move around a little, which would make them a little harder to hit, but also give insurgents a little time to breathe every so often, and also make it more realistic (please correct me if I'm wrong on that). They should also make them stick around a little longer, like in the previous builds. To balance this, if one gets shot down, it can act as a side objective, where if insurgents can capture it, they get extra respawn waves and time. If security can destroy the wreckage, insurgents can no longer capture it. This would make helicopters more powerful, but also sort of a double-edged sword, so that you may not always want to call one in. The biggest issue I see with it is choppers landing on top of buildings or out of bounds, which in that case, the devs would probably need to make it so the chopper is guaranteed to land where players can access it. I know this is a long shot, but I feel it would make helicopters more interesting and realistic, since there are times in real life where you wouldn't want to risk one, and if one gets shot down, you don't simply forget about it.
It ahould absolutely circle. Just hovering in the air would be asking for an rpg. The helo should have avoidance maneuvers for rpgs. Small arms fire should do nothing to the helicopter. Right now I have yet to have the blackhawk not arrive and crash immediately.
I think the potential for a blackhawk down objective where there is incentive for both teams to take the wreckage would be interesting. Maybe if insurgents take the downed helicopter they get a radio that notifies them when future air support is incoming, and if security takes it they get to call in another helicopter in a shorter timeframe? Agree on the flight pattern though, it's just an area denial weapon in PVP and silly RPG magnet in coop.