Well first off I would love to see a new and improved graphics engine much like the graphics in Doom 3, and I want the game to stay 1st person shooter. The new graphics with realistic shadows would give the Aliens a more horrific scary feel. I want to see shadows and darkness, flickering lights and more realistic sounds that can scare the living out of someone. They should have vehicles, the APC and also that plane in Aliens, don't know the name of it I want to see predator's have the same weapons as in Avp2 game but more improved and more effective. I dont know if you guys are familiar with a game called BattleField 2, but all the races in the game, alien, marine, and predator should have a set of 5 or 7 kits, assault kit, sniper kit, medic kit, enigneer kit, support kit.
(example):
Marines would have pulse rifles in the assualt kit. And the sniper kit should have the same rifle as in the avp2 game. For the medic they could have the pulse rifle without the grenade launcher, also should come equipped with medic kits to heal wounded soilders. The engineer kit should have the shotgun and land mines. The support kit should come with the smartgun. The kit system should also apply to the predators and aliens but with different weapons.
Predators should have an honor system, blooded, blooded hunter, Warrior, Blooded Warrior all the way to Elder. Each rank would get harder and harder to earn.You can get upgrades for weapons and other cool things like that. You can check your stats, how many kills and deaths you have gotten with each weapons, Special trophies. Earn awards, and other stuff. The honor system should apply also to marines, except they get ranked as private all the way to general. Should also apply to aliens in some way.
I got most of my ideas from the game BattleField 2 except I applied them to alien vs predator. There is so much more I am missing, but I hope you guys like the idea.