If what you're looking for is an amphibious aircraft, there's always the Skimmer, which we could use more of. I also suggested adding Cropdusters around RC a while back and it was positively received but never happened. I'm not sure if I like the idea of adding them right next to the Terrorist spawn, but making them more available across the map would be nice.
Seasparrow is hard to manage, that target lock works but you will have to aim it correctly to use it. I have made a dyom mission for fun just to try it out on npcs in a building and i ended up killing the person behind the target i was aiming at.
It would be nice to add one at terro and 1 at swat accessible only by those 2 classes.
I can show you how capable it can be if you are interested. If you know how to lead aim, it's strong against people on foot and slow vehicles. The only escape is outrunning it if in a vehicle or getting behind something, but even then you can be helikilled through the object, and it's not like a Rustler where it has to make a long turn to get to the other side.
I definitely agree that civilians should not be able to use it, it's like a Hydra in that you could just destroy every player in a tight group with it, regardless of team.
It is more powerful than Hydra with it's autolock always machine gun. You just need to push heli to forward down and shoot 
The Sea Sparrow is not more powerful than a Hydra. A direct hit without locking missiles from the Hydra is an instant kill to a car, and near-instant against someone on foot, depending on how much armor they have. It has the fastest speed possible. You can just outclimb any threat. You get hovering and the speed. It can easily shoot down a helicopter like a Sea Sparrow from a distance.
It is also not more powerful than a Rustler in the air either, it's just better against ground targets and could probably stop a Rustler from taking off. It can't aim straight down or straight up like a Hunter can, so it's vulnerable from below and above. They also presumably wouldn't have /ej.
Also, a little remark. The seasparrows deal as much damage per shot as rustlers or M4s (with a shorter cooldown time). And yes, they have auto aimlock, like vortices. So I don't think we'll ever find a place for them in our gamemode.
I don't think they really autoaim like a Vortex does. I do think they could have a place in a map like NSA where things are already batshit. I wouldn't necessarily be against trying them in a map like RC-- it needs something to make it more exciting, and they can be countered with a Rustler. As long as most cars can outrun it, it can be dealt with.
