We, the humble fans of The Witcher, declare that we would like Mads Mikkelson to play Geralt. 

At first, we thought Eric Bana would be a good choice; he has the bone structure, and can bulk up nicely. However, he's too benevolent for the role.

Then, we discussed the possibility of enjoying Jean Reno play the role; after seeing him play The Professional, we think that he can absolutely project the inner killer of Geralt, but he's a bit too old.

Then, we entertained the idea of Johnny Depp playing the role; he's one of the (if not the) best method actors in the entire world, so we know that an actor of his skill level will be able to properly convey Geralt's inner emotions if he bulks up, but then we figured that that would impede his progress as the scrawny Jack Sparrow (because it's very difficult gaining and losing muscle bouncing between roles like that).

Then finally, we decided that Mads Mikkelsen would be the absolute finest choice in the matter, not only because of him being originally European, but because his bone structure is wonderful, and he can play both rough benevolent and malevolent characters and medieval settings. We think that he could absolutely, if he were to get a bit more muscle, play the Geralt we'd like to see in the live action movie, and we're hoping that you would give him a shot.