Rebellion's AVP only used the Alien, the Praetorian, the PredAlien and Queen and although that worked I prefer more variety. Monolith's AVP maintained the right balance in my opinion for the time.
But I'm not opposed to the idea of having two or three variants of each caste as applicable
Praeto Egg/Egg/Royal Egg,
Praeto Facehugger/Facehugger/Royal Facehugger,
Praetomorph,
Drone/Warrior,
Runner/Defender,
Praetorian Guard/Praetorian Charger, Queen.
Just not interested in rather arbitrary acid specialisations myself personally.