EU material is supposed to be consistent in theme and atmosphere with its source material.
We didn't get that.
Instead, we get a great, plausible sci-fi setting made generic, its monsters rendered as mooks and its central character changed from a strong survivor to a gung-ho action hero. Not having read any Predator comics at length, I can't comment on them.
If the EU writers knew what they were doing, we would've gotten something far more consistent with the films.
The issue is that the fans we've had previously within the franchise didn't know what they were doing. The BS are the most obvious example. Anderson actually directed well, he just had to work with a shitty script and mediocre actors. I don't know if Fincher counts as a 'fan', but he was knowledgable enough to know to know about egg-morphing, so it's safe to say he had an interest.
Every time we've seen a shitty movie from a fan, it's been coupled with something else. We just need one that won't do things for the 'cool' factor, but for the sake of tension within the movie.