Interesting time article on the original series from Shatner's perspective. Sounds like a tribute to Leonard Nimoy:

"What was surprising to me was that rather than Capt. James T. Kirk, the character who received the most attention, and the most fan mail, was Mr. Spock. This was long before Leonard and I became friends, and honestly, I hadn’t expected it, and I was not especially thrilled about it. I was being paid the largest salary, I was out front for the publicity, I had the most lines, my character’s fate carried the story line, my character got the girl and saved the ship. The natural flow of events should have been that Kirk would receive the most attention, not some alien with strange-looking ears.

But the spectacular performance Leonard gave occupied all that attention in the beginning. . . "

"Most of the hallmarks that became associated with Spock, in particular the Vulcan neck pinch and the Vulcan salute, were entirely Leonard’s creation."

It goes on to explain how Nimoy, not the writers guarded Spocks character and ensured it was consistent.

http://time.com/4412892/star-trek-kirk-spock-william-shatner/