Why do so many action movies flop?
Simple - their baddies are not good enough. A strong good guy needs to overcome a powerful bad guy for a movie to really resonate.
Which is why Jaws worked so well for instance. OK, the bad guy was a shark, but he was a monstrous, unstoppable nasty shark. Same with the Terminator. Both were so much more powerful than the puny humans ranged against them, so taking them out was a truly heroic achievement.
Two movies I have really enjoyed recently have been Man of Steel and the 13th Warrior (an oldie but a goody).
Man of Steel features General Zod as the bad guy. He is so good as the bad guy because he thinks he is doing good - it's just sucks that the outcomes of his actions will be bad for the human race. He is totally driven by his desire to restart Krypton - and to him and his troops, that is a Good Thing. We're just unfortunate enough to be standing in his way. He isn't a cartoon bad guy who is doing bad things because they are fun to do - he is doing bad things because they have to be done to resurrect his race. He needs to kill a few billion people so that his people might live again. He's great.
The 13th Warrior didn't do very well at the box office, but I must have watched it at least 20 times. The characters are a hoot, and the interplay between them is done well. But again, you have a band of 13 guys facing a terrible, implacable foe. There is no reasoning with the bad guys (and there are a lot of them). They can't be bargained with. They can't be bought off. There is no discussion about the rights and wrongs of their actions - they simply want to kill everyone and eat them. There is no fluffing around with moral equivalencies and the good guys aren't torn with anguish about whether they are doing the right thing or not. They are facing a ruthless, evil enemy, and they need to kill them all. There are no pathetic civilians muttering about doing a deal with the enemy or "learning to get along". No one tries to understand why the bad guys are bad, and the only negotiating that they do is with the pointy end of a sword.