The Wrath of Khan alternative villain?

[Riley]

Hey! Stop speaking ill of the first Irish crew member of the U.S.S. Enterprise! In my head canon (which ignores the awful TNG films), Kevin Riley became captain of the Enterprise-B.

 

[Set Harth]

Maybe a "Trial of James T. Kirk," where some Commodore court martials him for controversial actions from previous seasons.

And then the Commodore turns out to be a future incarnation of Kirk...

 

[Vger23]

Ron Tracey. As a former Starfleet Captain, he would have been a very dangerous adversary. He also had every reason to want to go after Kirk...and he was relentlessly evil in "Omega Glory."

 

[The Salt Umpire]

It turns out that James Tiberius Kirk was the imposter and James Roy Kirk (WNMHGB) was the true Academy graduate, and now he's back for Revenge.

 

[The Salt Umpire]

Ron Tracey. As a former Starfleet Captain, he would have been a very dangerous adversary. He also had every reason to want to go after Kirk...and he was relentlessly evil in "Omega Glory."

Morgan Woodward chewed the scenery so well in both his roles. A delight to watch.

 

[Greg Cox]

There was a fan suggestion a while back for a Cold War-allegory finale for TOS that would have been thematically-appropriate.

Which is what they did for sixth movie, which is essentially the finale of TOS.

 

[Checker222]

Which is what they did for sixth movie, which is essentially the finale of TOS.

Yes. But the fan suggestion was more of a standalone 'don't let a WWIII missile confrontation destroy your incipient-spacefaring primitive planet' kind of allegory episode, directed at 1960s America.