But in Johnson's defense, he was a major character in a true ensemble, who got a lot of important scenes. Many of the episodes depended on his character. In contrast, Sulu was MIA for a lot of second season episodes and the only real impact was felt by Walter Koenig who suddenly had more to do. So, yeah, Johnson had reason to complain. Considering how many other people sat in the helmsman's seat and got just as many lines, Takei should whine less.
Well, when the original intro was done no one knew how it would all go, as far as cast members and storylines, etc. The very fact that as the series progressed Johnson did get plenty of meaty screen time makes it odd, to say the least, that he would come along years later and be complaining about that one little 'slight' at the beginning. Seems like the very good involvement that they gave him over time should have very nicely smoothed that over. Oh well....
It actually would be a bit insulting to Johnson and Wells that five of the seven were mentioned in the opening of S1 and the two of them weren't. But I've never heard either of them complain about it. I've only ever heard them state it as fact when an interviewer or fan is asking a question or wanting to hear a story (that has already been asked/answered/heard hundreds of times anyhow).
And as any fan of the show, or 60s pop culture enthusiast, has heard it was Bob Denver that was apparently the most miffed about it. He went to the studio asking them to change the theme to include them. When the studio said it would cost too much to re-record it he reminded them that his contract allowed him to be billed anywhere and they could either change the theme or bill him after everyone else. The theme was changed and, as the story goes, Johnson and Wells didn't find out why until years after the show had ended.
And when the original intro theme was done, it was a completely different style and lyric and only four of the seven characters remained unchanged from the pilot.
Back on to the ST ego topic... I also think Takei's ego has inflated his sense of the character's importance and his own.