kirk's character in the new movies is going through a major character arc of responsibility. A natural conclusion to such an arc is usually committing a major sacrifice for the greater good of the crew.
Wait, we've already seen that! yep, I submit that the story element of Kirk committing heroic sacrifice was better suited for the final film. Like Batman in The Dark Knight series.
What I'm getting at is that they have kind of written themselves into a corner if they were intending to have closure to this story in the final movie.
Let's hope they get creative.