Well, Dragonball is a bad example. Of course that's going to suck. Just look at the characters, they are just hard to transport into live action. The figure of the fighters with all those muscles (even kid gohan) and more importantly the face and hair. No human can have hair like Goku and eyes and eyebrows like him.
Therefore every attempt looks stupid.
Naruto is a bit different. It's easier to do in live action.
But I'd never let the americans do it. Let asia handle it, if it has to be done. They can do good films and special effects too and they have a better connection to namies/mangas.
But I'd propose another thing instead of a live action film. Make it like the Final Fantasy childrens advent. Both Dragonball and Naruto would look awesome animated in that quality.
PS: I wouldn't be so sure that they wouldn't westernize the whole thing. Just look at the plans for the Evangelion live action movie (if that will ever be made). Not even the japanese names of the characters remain.
"For Feanor was made the mightiest in all parts of body and mind, in valour, in endurance, in beauty, in understanding, in skill, in strength and subtlety alike, of all the Children of Illuvatar, and a bright flame was in him"