I do agree that most of the actors used in the PT are exceptional at their art and craft. Most of them gave at least memorable performances; however there are some actors who, unfortunately, have certain stigmas slapped on them due to past performances in films. Samuel L. Jackson is one of these actors in my opinion. I cannot see him as a Jedi, no matter how hard I try. I thought Mace Windu would have fit better if he were to be older, and wiser, much like Yoda. An older actor would have to be cast.
Again, in my opinion, Jimmy Smits does not fit the role... I felt an older-looking actor, perhaps Brain Cox (Profile) or Brendan Gleeson (Profile) would have worked more for the film(s)...