As a wicked awesome Alien player, I can see a third person view attracting more players to the Alien. First-person, when you're sprinting upside down then jumping from wall-to-wall, can be quite disorienting for a lot of people. As an Alien, I use all surfaces, but this is tricky and requires some practice to do well.
More players is a good thing, but I agree with all that the option would be best, Skyrim style.
Chupa also has a good point in that 3rd person cameras usually go tits up in cramped spaces. While playing the Alien, I'm sure that's mostly what I'll be doing anyway, so they need to get a smooth and very honed camera to pull it off nicely.