Why was Felix Leiter changed so much in the official EON series?
Correct if I'm wrong, but Bernie Casey as cast as Felix in Never Say Never Again in no small part because the theory was that if they got a black actor to play him, he would by default make an major impression one way or another. Because up until that point, Felix had really served as an inconsequential entity, since no actor played him more than once (until David Hedison played him in Licence to Kill, and that came right after John Terry played him in The Living Daylights).
https://qph.fs.quoracdn.net/main-qimg-6cd229b0c3d6b126dbafb89326470696
https://www.quora.com/How-many-actors-played-Felix-in-the-Bond-movies/answer/Melia-Janssen
It wasn't until Jeffrey Wright played Felix in Casino Royale and subsequently, Quantum of Solace, that we finally got a consistent portrayed of him.