So, why is most fans found the film just ok?
Oh yeah the film has its fans but when compared to the first two Predator films and even the AVP films Predators seems to have the overall smallest fan following and the Super Predators introduced in that film are not nearly as well loved as the Predators in the other films which includes AVP which have a huge fallowing (with the most notable being Wolf).
I think it comes down to two things and in order to explain this we need to go to the film who's title clearly inspired this movie's title, Aliens.
See in Alien it was established just how dangerous a single Alien was as it wiped out an entire crew of highly competent people who. In Aliens we were now going to see what an army of Aliens could do and would show once and for all why these monsters were so dangerous.
Now, this sounds like what we got in Predators as the first film showed how dangerous the just one Predator was as it like wised killed an entire company of soldiers so going up against more then one Predator would no doubt induce the same level of excitement as Aliens and we'd be getting a newer more dangerous Predator so this would have to be the Aliens of Predator Right?... Well... Here's the thing. While the crew of the Nostromo were highly competent at the end of the day they were really just regular people trapped with a monster which they had no way of being prepared for and in Aliens the people going up against the monsters this time new of the threat, were preparing for it and STILL got their asses handed to them, losing almost all of the Battalion in the first battle.
In Predator the heroes are standard macho men with THE action hero of the day at the start of his rise to stardom. And the following films had set a similar formula with a ensemble cast of badasses with even AVP and to a lesser extent AVPR following suit. Further more the Predators don't up the anti by including more dangerous human prey but instead bring in lesser prey that aren't really a threat to them but more of a threat to the prey they're hunting.
And worst of all is trying to introduce a new Predator that is supposedly more dangerous the original ones. But the problem there is the fact that the not only are these "Super" Predators NOT more dangerous then the classic Jungle Predators we've gotten uses too but it could be argued that they're actually LESS dangerous then the usual Predator as two are killed by one Human each while most of the kills are done by the Lead Predator, Beserker.
This has the problem of underselling the threat because we're TOLD that these Predators are more dangerous yet we're never SHOWN that and the regular Predator shown in the film who is beaten by the Super Predator only further solidifies that these Newer "Better" Predators aren't anything to write home about because the only reason Beserker won was because the OG Predator was tied to a stake for who knows how long and was likely starving & dehydrated and STILL put up one Hell of a Fight forcing Beserker to straight up cheat in order to win.
As bad as The Predator is and as stupid as the Ultimate Predator is it DID show why this Predator was so dangerous by easily beating an OG Predator in a matter of seconds. I HATE that scene but it did show that this was a whole new ball game and that this new Predator is a greater threat then the ones we've gotten use to.
This isn't to say that The Predator is better then Predators but I just felt that TP did to a better job at establishing the threat then Predators did... Okay it felt weird to actually somewhat complement TP
Anyway, Predators has it's strengths and many good and even great scenes but for me it falls flat mainly do due how poorly the Predators were executed and how it failed to live up to the idea of escalating the threat by just doing what Predator has always done instead of doing something new.
And I think this is a big factor in why Prey was so well received as the Predator in that film is shown to be as dangerous as the Predators we've known even though the prey it's going up against are using muskets, stone axes along with Bows, Arrows and Spears. Predators promised us a newer and more dangerous monster and deal with more of them but what we got was just more of the same while Prey brought the series back to what made it work and showed why it worked in the first place.
