You guys are nit picking to much.
Get it that a Movie will not look like the cartoon, or the manga. You think he needs a six pack to be Kakarot? No Kakarot is an Alien, if you've forgotten and is inherantly stronger on earth just like Superman.
Justin Chatwin is a good enough actor. Stop worrying about his physique, you guys sound like a bunch of girls complaining over him in Teenmagazines.
Just let the director tell a story. Movies are RE-Tellings, this means it doesnt have to look like the cartoon, and in my opinion getting Chatwin to play Goku is no different than getting Tobey double chin maguire to be spider-man...or if you didn't notice in Spidey 3. Being Super and Looking ripped to **** have nothing to do with each other.
Gokus character has strength of Will, determination, and a lawful good heart. He is a Hero, and as weve seen through many tales and films you dont need to look like a hero to be a hero.
I am glad he isnt all roided up. It grounds the film in reality, and gives us humans something to associate with. Cartoons have styles because they must be animated, however Humans do not look like cartoons, so just stop worrying about how buff he is going to be, jesus christ give the guy a chance.
Why don't you whiners go get ripped up to **** like Goku and convince them that you should be Goku, seeing how you all seem to be experts at making films, personal training, the DB Universe and gayly analyzing Justin Chatwins body....
GO outside! Go to Work!