I am in the process of reading Kelley's biography and in WOK there was a scene at least discussed (not filmed) where McCoy and Kirk would of had a moment to reflect on Spock's death.
This scene was forgo for the final scene between Kirk and his son. From a dramatic stand point I do understand why they decided to go with the son scene. Having Kirk's son accept his father in the end was obviously an important way to end their story.
However I think as a fan I would of rather seen that moment between Kirk and McCoy and their shared loss of Spock. That is the relationship I care about not Kirk and his son. After all Kirk and his son was only introduced in this movie whereas Kirk/McCoy/Spock was there from day one.