The only real drawback is that as of this writing he's 28, but I doubt that will cause that much of a problem because he has a boyish face, which will fit with the fact that I aged the main cast for added realism (and the fact that if it looks like a show for teens, adults may feel silly watching). I'll admit I don't know much of Hopper's work (I don't watch Merlin), but in some youtube clips I watched, I found him to be perfectly acceptable for Rand.
For Perrin Aybara, I decided to go with Game of Thrones's Joe Dempsie (right), and while he won't be the last name I pick from that show, I tried very hard not to cast too many people from there. I picked him because when I saw how much muscle he put on for Season Two, my first reaction was "Holy crap, that's Perrin!" At 25, he's a good age for the role, and like I said, he's already got the muscle. He also seems like he could play a genuine nice-guy. Perrin's a true gentleman, and a teddy-bear with muscles, and Dempsie is a likeable actor. Also, unless they take a seriously different direction than the books, Dempsie's contract for Thrones shouldn't last very long past this coming season.
Another 25-year-old actor, in this case Augustus Prew (left), is my pick for Matrim "Mat" Cauthon. I had a hard time with this one, but I picked Prew because he just seems like he's good at playing puckish guys, either with good hearts or without. Prew's got this tinny, high voice, but I'm not sure that's a bad thing where Mat is concerned. Like I said in my first post, I'm thinking his love of gambling and women should be played up, making him seem more like a medieval frat boy than a childish prankster. Not that this isn't true to the character at all.
Next up: the major supporting heroes!