Could only read the summary without subscribing. Nimoy has always been fussy about coming back to Trek, primarily to protect the integrity of his character, and the significance of his role in any movie/episode. This has proven to be a good thing before, ie; staying clear of generations (shudder as I type the word).
This would suggest he thinks the story merits being told, and that Spock has a central role to the movie, especially older Spock, to intice him to play the role. I've read elsewhere, but can't remember JJ took dozens or more takes to do a special shot of older/younger Spock doing the Vulcan salute, and interchanging images of Nimoys/Quintos hands to get it seemless. I think that is the passing the torch moment of the movie. (Don't know if this was in the full article you directed me to.)
You may find that having is not so pleasing a thing as wanting. This is not logical, but it is often true." Spock (Amok Time)