I really enjoyed AVPR as well although I am aware of it's flaws. One thing that may have helped character development was figuring out why Dallas went to prison in the first place and why he didn't regret doing what he did. Would have liked to find out more about that and probably would have made people care more. Like many have said it was to dark literally for some reason, so that is an annoying problem. I love slasher flicks but I did not think it fit with these characters and the franchises as a whole. The acting by the human characters were also pretty dull.
Some of the highlights that came out of it for me that made me enjoy the film were of course Wolf! Great design, loved the veteran Predator character. The fight scenes were exciting although the Aliens were not done the best. The final fight was pretty good as well. It also introduced new Predator technology that we haven't seen on film before. I liked the whip, those laser mines he used in the sewers or whatever they were. Those are the main reasons why we should all enjoy this film but I understand why the problems may have been to much for some.