Where's the Action: Fast 6 - is exactly what it is supposed to be. It has tremendous action sequences. It makes no sense whatsoever. I wouldn't pay to see it, but I would watch it when it comes on HBO, and would likely find myself stopping after landing on it during a channel surf years later. I don't see the loss of Paul Walker (rest in peace) as key here. None of these characters short of Vin Diesel are really all that critical. Actually, The Rock may be critical now, which says something about the importance of acting to the series. I still see the Fast series as something of an action movie throwback. The last gasp of the style of action film that dominated for so many years -- centered around a macho action hero, often a lunkhead.
Hmm. There's a time wasting idea. Let's break down the action movie eras more systematically.
The Cowboy and Soldier era. The activities of the heroes in these movies were, relative to everything that came after, realistic. That may be due partially to the limited production technology at the time. For the most part the heroes in these movies did things that exceptionally skilled, but still normal, human beings could do. This was the only era for truly human heroes. Calling out when these eras ended is certainly open to debate, but I'm going to say this one ended with the release of Dr. No (1962).
The Bond era. Bond and his ilk were highly idealized. They weren't just skilled at one thing, they could do everything well. In fact, there was no situation for which they were not prepared physically, mentally, culturally, and technologically, to overcome. This hero is the ideal man. Something we should all aspire to be, but something that can't exist in reality. A big trope in this era is the villain believing he's got the hero subdued, but the hero -- always prepared, always capable, always superior -- satisfyingly turns the tables. Note: I put both Bruce Lee and Indiana Jones in this category. My instinct is to say this era ended with Rambo and Conan, both from 1982.
The Lunkhead era. Grunts and proles became the hero. Again, the humans are shown to have superior skills, but this time there is no pretense of intellectual or cultural superiority. In fact, there is often the suggestion that brains and manners are working against the villain. Nope, with these guys it all comes down to fists and firepower. Stallone, Schwarzenegger, Van Damme, Segal, Bruce Willis, and a host of lesser knowns -- they cranked out action flicks the way studios crank out horror flicks today. Interestingly, the vast majority that came out during the glory years sucked beyond all reason. Only in the era's waning did some of these become quality films. No, not art, but they finally got proper pacing, acting, and production values. The end of the Lunkhead era came with The Matrix (1999).
The Superhuman era. This is the world we live in today and it needs little explanation. Lord of the Rings, the various Marvel movies. It's all about being beyond human. And to do that with economic efficiency you need high-end computer effects.
Note 1: It is certainly possible to get a good action flick that is out of it's era chronologically. The Mission Impossible series is Bond era. The Fast series and the self-referential Expendables are Lunkhead. We've seen soldiers out of their era, too -- think: Black Hawk Down, Saving Private Ryan. But Hollywood is not for risk takers. The formula and the style for the bulk of the films will always conform to the era.
Note 2: I don't know what to do about Star Wars. Chronologically it's Bond, but it's definitely not Bond. Thematically it's Cowboy and Soldier, but there is an aspect of Superhuman to The Force. Not sure where it falls. I am only speaking of the first trilogy. The abominable second trilogy is clearly Superhuman.
Note 3: The pre-Abrams Star Trek films are merely extensions of the TV shows so don't qualify for this list. The Abrams Treks have the same issue as the first Star Wars trilogy, although given all the techno-Deus ex Machina they employ I would probably lump them into Superhuman also.
Note 4: The Daniel Craig Bond films are probably still Bond but they veer well over to Lunkhead.
Note 5: I need a life.