Rock's best movies are those trio of disaster flicks, even if they were all interchangeable.
Rampage, San Andreas and Skyscraper are very good "plane" movies. They kill time, the plot is pointless but not embarrassing and has some decent action. He wanted to get cute with Hobbs and Shawn and other shit, and it's what made people turn on him.
Cena doesn't give a shit, so sometimes he signs to absolute garbage, but he's usually the best part. I don't think Cena is a good leading man, but he's great at playing off someone, kind of like Big Dave.
Rock would probably be fantastic, but he can't help himself.