protomorph physical features.

I think I read that the protomorph was primarily quadrupedal due to rules for movie monsters in Asia.  So if that is true, Fox crapped on the inherited trait concept for Asian box office cash. 

Godzilla isn't a quadraped.  THe lifecycle that we know from the old movies hadn't been established yet so the lifecycle of the Alien Covenant xeno and protos don't really have to cohere exactly to the cycle we all know from the old movies, since they are ahead (in movie time) of the proto and xeno in AC.  They are close though leading the audience to believe David is on the right track to perfecting the lifecycle that we know.

And this isn't 1960 either.  Not saying I'm right, just saying that is what I recall reading.  Past canon blown apart again in that the runner taught us they mimic thier host, except in Covenant the damn thing looks like it gestated in a grasshopper.

ALIEN the Xenomorph was limited to how much you could show for a Man in a Monster Suit and so the Xenomorph design has evolved with the times and i would say the ALIEN: Isolation is more a visual representation of the Classic Xenomorph if we ever get to the one from ALIEN again.

The Animalistic Approach was a bit odd, it did not quite have the same cautious predatory instincts like we see in Alien, or Alien 3 but then those in Aliens and other movies also seem to act a bit animalistic too.

I think RS will stick with the Xenomorph in AC being the Precursor to the Alien one, and i expect Davids creation has some Evolution to go before we get to those Eggs on the Derelict

My point, I guess, is the man in the suit was better.  Humans are alpha predators (although i've learned here that some hate that fact), but facing an enhanced humanoid verion of us is nightmare-ish.  especially when we birth it!  Facing a hard plated cougar is not, not for me at least. I guess we are all different in that lane.  BigDave, your optimism in RS is commendable.

Indeed it was those almost Human Quality and Aesthetic that gave the Xenomorph the Presence that it had, i think some restrictions came from the Man in a Suit, and i feel the Aesthetic they are taking now is like we see in the Queen Alien in the Franchise as far as the Legs. 

This is something we see with the Xenomorph in AC, but its also the difference we see in Alien Isolation Xenomorph compared to Alien. I think by the time we get the reveal of the Classic Xenomorph again, it will go with the Aesthetic of the Isolation game, as opposed to the Legs of the 1979 Movie.