First of all, I'm a huge fan of Oded Fehr and I think he would have been excellent in the role as the Prince of Persia. But that's just the problem right there. He isn't very prominent and it takes a prominent A-list actor to make a good A-list movie.
Cases like that of
Gabourey Sidibe are very rare. No risks could have been taken in the creation of a movie such as the Prince of Persia which is based on an already set arena.
It's not personal, just business.