I never thought of this until Into Darkness but now can't help but wish it was the case. Basically, it occurs to me that as much as Khan and Kirk are archenemies, a fight both mental and physical between Spock vs. Khan was something that would have been interesting to see. We got a hint of it in Into Darkness and that got my mind working that Spock really is the ultimate rebuttal to Augmented Supermen like him.
Spock is a physical and mental powerhouse equal to or superior to Khan, but Spock chooses to serve as the Number Two to Captain Kirk because leadership is not determined by either his raw power or pure knowledge. He also doesn't feel diminished by not being a leader and captain but happily works in a subordinate role.
Khan would just not get that and it's a shame we never saw them talk about it.
Spock is a physical and mental powerhouse equal to or superior to Khan, but Spock chooses to serve as the Number Two to Captain Kirk because leadership is not determined by either his raw power or pure knowledge. He also doesn't feel diminished by not being a leader and captain but happily works in a subordinate role.
Khan would just not get that and it's a shame we never saw them talk about it.