Why It Should Happen:
1. His name literally has the word “rock” in it
The Thing looks like a rock, so what better reason is there then to give Dwayne ‘The Rock’ Johnson the role. It may not be the most sound reason, but it just seems like a sign that he was destined for this role.
2. Would create unthinkable “buzz” for the film
If you didn’t think the Fantastic Four had any “buzz” joining the MCU, this would deliver it. Johnson is a global star whose film franchises (Fast and Furious, Jumanji) have done quite well at the global box office. If there was any question that it was a financial risk to do another reboot, I don’t think they’re actually is, then this would erase that instantly.
3. Johnson is a perfect fit
He would be a good fit for the character in terms of personality. Like I mentioned earlier, in the comics, Grimm time from time provides light humor to soften the story. Nearly all of Johnson’s roles in film are just that. A character seen as a hero, big, strong, tough, but also provides a few laughs to make the story more enjoyable. This is precisely how the Grimm is portrayed.
If Johnson plays the role, I still think Grimm’s rock form should be all CGI like Bell’s was in 2015. Even at 6’5″, Johnson’s height and big frame is still not near the like of Ben Grimm’s modern take, which is around 7 feet tall. As we saw in Avengers: Endgame with Mark Ruffalo’s Hulk, it is possible to display an actor’s appearance in a taller/bigger role. During shooting, actors would wear a green screen type suit that can make their appearance change in post-editing. This is how I would hope Johnson’s “Thing” would be seen.