ST: TOS had plenty of excellent directors -- Marc Daniels, Joseph Pevney, Ralph Senensky, Marvin Chomsky and others. Given the time and budget constraints, their work is nothing short of amazing.
But there were other television directors at the time who could have worked on the show, but didn't. Two that I'd loved to have seen helm some episodes are Leonard Horn (he did beautiful work on The Outer Limits and Mission: Impossible) and Sutton Roley (superb direction of several Lost in Space [yes, really] episodes including "Wish Upon a Star" and "The Anti-Matter Man.")
Others?
But there were other television directors at the time who could have worked on the show, but didn't. Two that I'd loved to have seen helm some episodes are Leonard Horn (he did beautiful work on The Outer Limits and Mission: Impossible) and Sutton Roley (superb direction of several Lost in Space [yes, really] episodes including "Wish Upon a Star" and "The Anti-Matter Man.")
Others?