You can only imagine what the end result would have been like.
It would be a contradiction. What did Riker say to Troi at the end of TATV? "Now, I'm ready to talk to Captain Picard"
In "The Pegasus" it's clear that he won't talk because he follows Admiral Pressman's order not to discuss it with Captain Picard.
So it's like "I'm ready to talk to Captain Picard, but I'm following orders not to talk to him."
When he finally is "ready" it's not the result of his holodeck history lesson but owed to the situation the Enterprise-D
ends up in: The Romulans have sealed off the asteroid's exit and the only way to get the Enterprise-D out of there is by using the Federation cloaking device.
And for that, quite simply, he did not need this history lesson. Therefore it is a logical conclusion that TATV is a piece of holodeck propaganda, as it has been correctly suggested.