Re: Star Trek III - The [Speculation Begins] (Spoilers)
5 Year missiony stuff next movie, with a relationship for Kirk and Carol.
Spock Prime major subplot showing New Vulcan, concluding the characters arc.
Followed by :
A Klingon-centric movie.
A Giant Cream Horn / Commodore Decker
Khan back in Trek 4, 5 or even 6.
Soon oh soon the light, Pass within and soothe this endless night, And wait here for you, Our reason to be here...