Rev, wake up!
This is serious discussion! Life or death matter!
I want the MCU to get it right for Namor, as they did for Avengers Big Three!
The thing is you can only do so much with the time of preparation actors have to build an impressive physique. Chris Evans (6'0") had done it before for Human Torch in FF and other movies, Henry Cavill (6'1") the same. Still Jason Momoa towers besides them too as he is 6'4". Cavill (6'1') has gained a considerable amount of muscle mass thru the years more than Evans. Only Tom Welling and Chris Hemsworth both 6'3" from all the actors that play superhero have the height and frame to compete. Lets discard Tom Welling as he never wore the suit for Smallville so I doubt he would want to be Namor.
And there are actors that have body types that don't lend well to muscle mass like Ben Affleck (6'4") and Armie Hammer (6'5"). They get big but its hard for them to fill the limbs and get cut.
Both Jason Momoa and Chris Hemsworth came from backgrounds were their bodies and being shirtless on screen most of the time was a requirement. Momoa in Baywatch and Hemsworth in Home and Away. Their bodies were selling first and the acting came as second. Just as the wrestlers to actors Dwayne Johnson, Batista and Cena.
If you are thinking that a guy known best for acting and the occasional shirt off is going to do great, think twice. Look at Robert Pattinson as Batman (didn't even want to workout) and Zachary Levi as Shazam. Lucky for Pattinson Batman can go the route of Iron Man. And poor Zachary Levi did as much as he could but in the end had to wear a muscle suit.
What I'm saying is that its hard to compete with Jason Momoa but we must if Namor is not going to end up as the beta of ocean heroes and a joke like the Deep
that is even wearing a similar suit to Namor's leotard.