Add CGI droids to Wrath of Kahn?
Add a terrible CGI jazz number to the opening of Final Frontier instead of Row Row Row Your Boat?
A scene where Kirk walks around one of the whales from Voyage Home and steps over their tail?
What would you add? Take a film and go to town.
Star Trek VI: Undiscovered Country
But all the set redress shots are redone with CGI. That way the President’s office doesn’t look like Ten-Forward with a curtain, and Main engineering looks more period accurate.