I've been pondering about using the health rules from Coriolis in the Alien RPG Campaign play myself, it does cause a bit of a conundrum. On one hand, as far as I can tell, it does little to reduce the lethality of the Xenomorphs. Most of their signature attacks, the deadly ones at least, trigger if their victim suffers one point of damage. The other attacks are mobility or stress based. The victims total health doesn't seem to be a contributing factor.
On the other hand, it raises the durability of characters against every other threat they will face, which is a mixed bag. It will raise most characters Health to around 7 or 8. Normally, a Pilot, an Agility based character, would probably have 2 or 3 Health maximum. Anything other than a base success hit with a pistol will drop them in one shot. I can see that being a bit problematic in Campaign play, if the first time combat breaks out they take an unlucky crit hit and die right there. Fine for a Cinematic scenario, a bit rough for a Campaign.
Contrast with a Roughneck who now has 8 Health and the Resilient talent on top, who can now potentially shrug off multiple Assault Rifle shots and due to how the Talent works, effectively has 8 points of natural armour. However due to all tests being resolved by rolling 6s it can be boom or bust for taking or shrugging off damage.
So, in short, using the Coriolis health system doesn't save you from having your head bitten off by a Xeno, but certainly lessens the threat from literally every other peril you will encounter, unless I've missed something.
Edit: That all said, there are only four results on the Critical Hit table which result in instant death, so perhaps embrace the low health for Campaign play and just prepare for characters to be scarred and maimed if they survive long enough.
Edit the Second: Nicking an idea from Warhammer 40k Wrath and Glory, if a character has a visible scar from a critical hit, give them a +1 or -1 dice for Command or Manipulation tests depending on the situation, think Hicks acid scarred face if he'd survived the events of the movies. Obviously this wouldn't be a cumulative bonus.