The nerfed Annihilator might as well not have weapons. In GTA IV, the minigun had explosive rounds with splash damage, and you could blow up cars with it. In GTA V, if you put one person in an open field with a pistol and another person in an Annihilator, the person with the pistol will likely snipe the pilot before the helicopter gets a single hit with the minigun. You can also keep the minigun locked on a car for 10 seconds, and it won't blow up.
The Lazer has rockets and explosive minigun rounds, but the draw distance means you can't see other players until you're close enough to be one second from crashing into the ground. If you're really good with it, you can start pinpointing the rockets after a few passes.
The only aerial weapon that poses a threat is the Buzzard's rockets, especially with a copilot manning the camera. It's almost too easy to get kills with it.
Only the Ahnialator from Gay Tony had explosive rounds. Vanilla GTAIV was regular minigun rounds.
I need to use the blackhawk more, I don't think its that difficult to aim. It's just a super clunky helicopter to control especially with how responsive it used to be in IV