It's not just the over-the-top action scenes. It's Vin Diesel trying to outdo everyone to ensure he's top dog in the franchise and that no one forgets that. Ever since he was given that producer role, Toretto has become more and more of a caricature while the rest of the "family" has remained relatively the same. He's catching engine blocks with one hand; taking out Hobbs with little issue; catching people in mid-air; driving cars out of flaming airplanes with no injuries, despite crashing and flipping numerous times; driving cars across three buildings; stomping fucking parking garages and causing them to collapse; and just about all of the ridiculous shit that's in this last movie.
They were fairly easy to look past in those last films, but perhaps it's the loss of Paul Walker, but F8 just makes it so fucking ridiculous and apparent that he's clutching his star for dear life to ensure no one overtakes him. It's like everyone in this universe shits their pants when they hear Toretto because no matter how strong, skilled or badass they are, he's always going to be better -- despite no story justification to support it.