Two Aliens that do f**knothing when Wolf grabs 'em by the throat; multiple Aliens that stand here, still, doing nothing waiting for Wolf to do his move; two Aliens that don't notice a shuriken incoming and they stick their head out; the Requiem Aliens were just plot-conveniently, and rather visibly, downgraded and upgraded in every sequence they star in. They're quick to take out the National Guard guys, yet with Dallas one stands still until he actually shoots him. The only 'good' one as you said was the one in the power plant.
The AvP Aliens were efficient and mostly did their job; it's been a while since I last saw the film, the only scene in which I recall them going bad was right before Scar and Alexa take the sled.
And the AvP Predators aren't pussies at all, since one was taken out by surprise, one stood for 3 minutes in a melee combat against an Alien and the other one kind of killed four Aliens by himself, before getting owned by a 6 meters tall Alien Queen. Wolf appears as a super-skilled Predator in the film he stars in, but he really doesn't know much - he has his back uncovered multiple times, he's stupid enough to think to shoot an Alien point blank, he wastes time skinning the cop while he should clean the infestation, et cetera. He appears super-skilled because right when he appears onscreen, the Aliens suddenly become braindead.
