Why all of a sudden am I forced to choose? Characters or fighting? F*ck that! I want both! And Bishop is right. You can't write a script with no dialogue, it just won't work. You need a plot and you need characters to move it forward.
If there would be no humans, who would advance the plot? Predators? hell no, because apparently if we learn anything at all about the Predators that wasn't already stated in previous films, it's automatically considered bad regardless of weather or not the idea is seen on film. Aliens? Nope. You Need humans to make aliens.
Do you think the Alien film series would be as great if it wasn't for it's characters. The Nostromo crew, the marines, the prison inmates, and the hell with it, even the Resurrection characters had some good moments.
Maybe hardcore fans who want nothing but mindless fighting that makes no sense can be easily pleased, but general audiences are going to want more.
Why do you think the Spider-Man films take so much time for character development, despite being multi million dollar projects. It's because even though fighting and action is good, no amount of special effects will be able to compensate for shitty writting.