I have always found the design of the xenomorph to be a interesting design to say the least. but what it does do is blow away the previous conceptions of what an alien would look like. For that I feel the deign is successful in my mind along with every other design element in the film.
It's interesting, but absolutely ridiculous. Acid blood? Give me a break. Blood is used for TRANSPORT, and acid destroys things. LOGIC. If they had acid sacs under the skin I could see that but acid BLOOD?
I also find the egg design to be silly. If these creatures are engineered as weapons, why even design them with an egg phase since eggs are easily destroyed? If I were designing a bioweapon I'd bypass the eggs and have them just be born as facehuggers directly. The facehuggers are destructive but the egg is worthless.