20 Things You Didn't Know About Star Trek III: The Search For Spock (1984)
10. Commander Kruge, Thy True Name Is Adama
In a case of Nimoy v Bennett, there was a disagreement over who should play Commander Kruge, the Klingon responsible for the death of David, and, through his actions, inspires Kirk to destroy the Enterprise.
While Christopher Lloyd would end up donning the ridges, Leonard Nimoy wanted Edward James Olmos to play the part. Olmos is most recognizable these days for playing Commander - later Admiral - Adama on Ronald D. Moore and David Eick's re-imagined Battlestar Galactica series. However, at the time, while far from an unknown actor, he wasn't high on Harve Bennett's list of potentials.
Nimoy pushed to hire him, though Bennett insisted they open the role for auditions. After several rounds, coupled with Bennett's insistence that Olmos simply didn't have the physicality to effectively portray a Klingon, Christopher Lloyd won the part instead. This came with its own issues, chiefly among them being that Lloyd was best known for his work in comedy, but it was still a case of Bennett winning the day.
Olmos, though out of the running for a Klingon, would later be considered for the part of Jean-Luc Picard as The Next Generation entered pre-production.