A bit late to the party but I'd point out that there have already been several things covering the society of the Predators, albiet not in the form of a movie. Simply put rambling on about a hypothetical society in enough detail to matter is likely to cause some serious problems for a movie people would be going to watch for the action appeal. At least if you wanted to give enough information for it to matter.
At any rate, the original "Aliens Vs. Predator" comics... which is the storyline that people were hoping they would use, but never did, kind of went into this a bit and managed to get the points accross without a lot of exposition. Albiet the nature of this storyline kind of invalidated the direction a lot of people apparently wanted to go in.
Simply put the gist of the matter is that Predators are more or less forbidden from going after "people", in this case races beyond a certain level of technological sophistication. This means all of this junk you see in video games with Predators going after Marines and colonists basically doesn't happen, or isn't supposed to. By the time a species has space travel, it's more or less off limits.
The original comic premise featured the idea of the Predators dropping some aliens on a planet to hunt them, where there was a human colony they were not supposed to mess with. An accident with a colonist destroys their drop ship, and the predators more or less freak out since a lot of them (most of the survivors) want to go kill the humans along with the aliens, but a few of them hold to the law and refuse to do this. This leads to the last surviving "good" predator teaming up with a rather kick arse female corperate to fight both Aliens and other Predators, and eventually they wind up leaving together for the Predator homeworld.
Books (not comic books) were written on the subject later, which further expanded this storyline, and covered a lot of what happened when she went to their homeworld. In simple terms given that humans were one of the species that were preyed on, the idea of humans being advanced enough to be off limits is something of an issue, and she winds up doing a lot of fighting there and winds up becoming something of a liason.
It's also noteworthy that what the Predators use for technology depends on the hunt they are going on. Part of the point is a challenge, and this is why you don't always see the 'best' weapons in differant storylines for any given situation. What's more, all arguements about predators proving themselves are fairly accurate, and if I remember there is a degree of scorn for someone say showing up with visual camoflauge, a force field, and 200 weapons to hunt some primitive with a spear. This is why presumably Predators have been killed by humans with black powder weapons, and you've seen comics with say tribal natives having predator skulls attached to their shields. It's about the principle of the thing, the prey is supposed to have a chance or else it's pointless.
A point also made (and something that makes a joke out of some of the various crossovers) is that while advanced compared to the 20th century, the Predators don't exactly have limitless technology. This is one of the reasons why they try not to provoke other advanced species beyond a point. While very good warriors, actually dealing with the trained warriors (Marines) of the "Alien" timeline with their weapons is a bit more even than you might think. I vaguely remember one of the books I read making this point about the explosives in the projectiles the armed forces were using (the reason why they weren't supposed to use them in "Aliens" for fear of damaging a reactor) and getting hit by that (especially given that they were allegedly propelled by an electromagnetic rail to much greater speeds and so on) compared to a 20th century gun. Not to mention optics and motion sensors vs. visual camoflauge and the fact that mega-tech ceramic armor intended to stop (sometimes) explosive rail gun rounds is not entirely ineffective against what the predators were using (ie it's not a trivial matter to stick a hand claw through that, like it was with kevlar).
It's probably been 15 or 20 years since I read any of this stuff, and doubtlessly there are plenty of contridictions out there (and I won't claim my memory is perfect). The basic point of all this rambling is that there has been enough world building at various points where you can probably find someone answering any question you thought to ask about "Cameronverse" concepts, and some you probably never thought of.
Honestly though, it seems that most of that is simply ignored by the makers of movies and video games. For example when it comes to the cinematics of the last "Aliens Vs. Predator" game (which Unskippable criticized) I was kind of miffed with how they had a Predator ship simply decloak and open fire on an earth military vessel. I mean while things like that could happen, it seemed to ignore a lot of what was established, it wouldn't have been quite that easy to take the humans out (though they probably would have, they do have a bit of an edge technologically, not to an extreme degree though), and it would have been a pretty big issue which all of the crew would be unlikely to agree with. While the Marines do have a chance in that game, I would also tend to think that without some kind of extenuating circumstances preventing them from using their weapons until their numbers are down (like in Aliens) or a lot more Predators than the handfull that dropped, they would have mopped up everything on the planet in ground combat in short order. Discounting exceptional individuals on either side the general odds in some of the books basically seemed like 1 Predator being worth 2 Marines on average, and Aliens needing like 50 to 1 odds to handle either if they could use all their stuff.
