This may sound stupid for some people but anyways...
Have you notice that all bad Alien movies have something to do with A.D.I.
All good Alien movies were done by another special effects company.
Giger, Stan Winston?
I am not saying A.D.I makes a good job in terms of design (like the Alien dog and Wolf)
but all bad Alien movies have to do with Tom and Alex.
Dont you feel the same?