So here's Kirk's quote:
This is the final cruise of the Starship Enterprise under my command. This ship and her history will shortly become the care of a new generation. To them and their posterity will we commit our future. They will continue the voyages we have begun and journey to ALL the undiscovered countries, boldly going where no man... where no ONE has gone before.
If you don't think that's foreshadowing TNG, then I'm not sure what to tell you. Because that quote is chock full of TNG references. "Generation," "continue the voyages," and especially "ONE," since TNG changed the opening monologue from "man" to "one."