While I don't particularly hate the AVP/AVP:R designs, it's just a few things that really bother me about the designs.
The main issue I have with it is something that actually started with the Alien design is Resurrection. The rear cranial area (it's flat on the bottom). It really doesn't look good, and when trying to think of a reason WHY ADI did that, I can't think of any that makes a bit of sense.
With Resurrection, it could be partially explained away with "their DNA has been altered/contaminated" by Ripley/human DNA, and further augmented through cloning a non perfect specimen, etc etc...
But what was the reasoning in the latter films, again?