Is there a motive to switch him out?

Probably the same old motive, he was ready to spill the beans. And they couldn't have that, he was still too popular, too vocal, and probably knew a bit more than your average actor, of the evil things happening there.

I'm also guessing the Truman Show movie he starred in opened his eyes. Hard to be the main actor in such a movie and not realize how close to the reality it is. I loved the last part, after Truman (played by him) found the exit door and was ready to go through it? Christof (who represents the Demiurge, the false god creator) makes his final appeal: "You can't leave, Truman. You belong here with me. Talk to me. Say something. Well, say something, goddamn it. You're on television. You're live to the whole world.". The Creator demanding acknowledgement, demanding the soul recognize his authority, begging the escaping consciousness to stay in his control. And Truman's response is perfect: "In case I don't see you, good afternoon, good evening, and good night". He acknowledges Christof only to dismiss him, using his signature TV phrase one final time before stepping through the door into the unknown, into the real world, into liberation from the only reality he's ever known. And Truman's final crossing of water and ascent through the door as the souls escape from The Matrix. Even the name Cristof is saying to us the Anti-Christ. Stop the awakening.