The first half of Predator is essential as to why it is a classic, not it's sequel. The title predator has multiple meanings which is the "Name" of the unnamed Alien and it refers to man themselves as predators of each other and other "lower" animals, but it's main concern was hunting of each other. At the start of the movie man is no longer the predator, he is the hunted, he just doesn't know it, just like the animals we hunt. Mid film they gain awareness and by the end, neither are the predator or both are depending on how you see it.
The Predator is active during the first half, stalking the humans running around in the Jungle, you get to see it's aftermath with the skinned corpses, Billy's statement about the first team firing in all directions and hitting nothing with parallels to their own team's actions later, then his growing unease when his teammate flaks him off by saying that Billy is afraid of no man. The Predator is shown to be so good at what it does, it leaves nothing to find except for what it wants us to find.
The first half is to establish that Arnie's team are the top "Predators" and what better way to do it that show them blowing away dozens of guys while remarking "I haven't got time to bleed". Or would you have preferred it if they just talked about how badass they are. Arnie's team are the furtherest thing from red shirts you can get. Each are shown to have a unique personality, histories, relationships with each other, differing motivations. Without this properly done buildup, it's no better than a slasher flick or those terrible AVP films.
You just wanted the Predator to dance around killing people, but you can't have that. The Predator is an alien, not even that in a way, it's more than a concept, there is no way for you to relate to it, what are it's motivations? To hunt and nothing else? It would be no different than having a camera follow Jason Vorhese, a bunch of people die, but then what?. If you just want to watch a bunch of people get killed in sadistic ways, go watch Final Destination.
The problem with Expendables is that it does none of what Predator does. Stallone's team are not shown to be remotely a cohesive group, the guy with the most personality happens to be the guy who stays behind and most of what he said is nonsensical. Jet Li's comedy routine gives him more personality than Stallone has. Terry Crews character doesn't exists until the shotgun scene. Even when something is real like Stallone himself getting pile driven and actually getting hurt doesn't come out right with everything cut to shreds, shaking in a poorly lit, rubbish angle. Throw in the poorly shot, shaky cam, lazy CGI, awful editing that is the rest of the film, makes Expendables an object lesson in how not to make an action movie of any sort.
This is a bit late, but I had to pin down exactly why I didn't like Chronicle. The key is that I didn't believe Andrew's fall or that he ever fell at all. Andrew was barely a character as everything he does is prompted by external factors, he never does anything for himself, not to mention he is an idiot. The writer hands him an idiot ball and Andrew never lets go. People rob convenience stores all the time out of desperation with nothing more than guts and maybe a gun. Andrew has super powers and he utterly fails. He embarrass himself shouting "Come on COME ON" to himself while taking the money out of the till. The super hero battle in the end is a complete disconnect in tone with the rest of the movie and the found footage camera angles become a liability.
If I was to write Andrew's character, I would have written him starting off as a normal person who gets an increasing amount of **** happen to him with the only real sense of agency he has is from his super powers. I would keep his relationship with his mother since that is the one thing that works, but they never really used it. Keep her sick, but have Andrew not only discover he has the power of death, but believe he has the power of life. So you have him reading and preforming medical experiments on animals with his powers, trying "Fix" them. Eventually he tries to "Fix" his mother and utterly fails, but only after he goes on a crime spree robbing banks and drug dispensaries for supplies and equipment.
After he kills his mother he is pissed, angry, but not raging like the hulk. He heads downtown systemically destroying the society that has let him down. Insurance companies, banks, even hospitals.
You don't kill Steve. It was unnecessary. Force them to have a 2 on 1 fight, with the only thing holding them back is that they believe they can bring him from the brink. But this is misguided as he has gone too far to come back. None of that Apex Predator BS. Andrew is tired of the lack of control in his life, he wants to play God, and he has the power to do it. Now you have a proper reason to have a city wide battle not because Andrew "Hulks" out. Andrew sees Matt and Steve as part of the society trying to oppress him.
Who wins and how no longer matter, Villain wins if they want a sequel hook, heroes win for closure with heroic sacrifice for extra points. The point of the movie is to test the characters not by giving them adversity, but power. Chronicle was mostly style There is a massive disconnect mid movie and it utterly fails during the transition. It not that they could have a transition, but it's done poorly enough that you think George Lucas wrote it.
There were some genuinely good points like the progression of their powers which really worked well with the found footage angle. The flight section is great in general, but missing some minor details. The magic show should have been the turning point where he wants and can seize control. Instead in the after party they revert him back to form as a loser from which he never progresses away from. Andrew dies as a unsympathetic loser and is all he ever was.