Ok...3 things off the top of my head that make the Alien better...that ADI just can't seem to get right...
1) No turkey neck...I mean that in the length and the giblets that are all over 3 and 4. I know the length is partially due to the way the suit is made...it just drives me nuts though.
2) The "eyes" that aren't eyes. Those glands on the original that would be about (below actually) where the skulls ears would be. They look like eyes but they aren't. I always thought those "eyeless eyes" were creepy in a good way....and they seem to be gone now.
3) The proper implementation of bio-mech. Hoses and tubes are great...but they need to look like they are integrated for function but not necessarily the exact same color and shades as the bio portions of the creature.
...ok...one more...
4) No more "Pumpkinhead" bodies...