I'm about as anti-console as anyone here but how does making Alien gameplay 3rd-person have anything to do with consoles? The latest AvP was designed for consoles and it had first-person Alien gameplay, just like its PC-exclusive predecessors.
I'm guessing the reason why Gearbox went with 3rd person is that it's less work. They already have to make a 3rd-person character mesh, art and anims for multiplayer so going completely 3rd person saves them from having to make viewmodel versions of all of that. It also makes it much easier to handle grapples, which are always tricky in first-person multiplayer games.