Oh, regarding the title of the thread: the ego issue will NEVER be put to rest. Not by us, anyway.
But did he intentionally tank a scene with Takei that would have given him (Takei) command of a starship 4 films earlier than VI? Hnnh? HNNH!?
At least I think I read that.
Takei commanding his own ship in Star Trek II? Where does that scene come in? I've seen the film and special features and there is no mention of this.
More importantly, most people didn't really care to see a Captain Sulu. One gets the sense that Takei is sore that he never got his chance to be Captain Kirk.
Sulu was supposed to get command of the Excelsior, I believe, in Star Trek II. Kirk was supposed to mention it in the shuttle ride to the Enterprise; notice Sulu's line cut off halfway through: "any chance to go aboard the Enterprise" - he is clearly supposed to keep talking. Then they cut to the exterior shot and then back to Kirk talking about Sulu back "at the helm for three weeks." From what I've heard (from Takei somewhere?), Shatner kept screwing up his lines (intentionally) and it turned out badly so it was cut.
I call shenanigans. Would any director let this crap go on? Nick Meyer seemed to know how to handle Shatner. It was most likely just not considered relevant. Jimmy Doohan also accused Shatner of having the "Scotty's nephew" references taken out. They sure gave Shatner credit for a LOT of behind the scenes control. As my mom always said, though; consider the source.
Then in Star Trek 6, Takei supposedly told Shatner, excitedly, that he was getting his own command at last. Shatner looked at him, non-plussed, and said "why? All of the action takes place on the Enterprise?" Shatner was confused as to why an actor would want to take himself away from the main action. That's actually a good point, but Takei did some of his best work in Trek 6, so what do I know? He obviously relished the change in Sulu's role and it was an interesting choice to have two starships play a large part in the climax. Although, I would have preferred to see 1701 have more to do in the fight than being a punching bag for Chang.
Back in the 70's, the Star Trek cast was portrayed, in books, to be closely knit. "The friendliest set in Hollywood" according to David Gerrold. I loved that. Honestly, when all this Shatner Bashing started, I was bummed. I preferred them to be close. Now, I dno't care at all, but as a kid, thinking they were all friends was pretty awesome.