I remember hearing something about that but I always assumed it was just a bad fanflick script! That would have been truly awful IMO. In some ways it was quite nice having it just being Picard and Kirk, the problem I think was that neither of them got to show what makes them individually good Captains.
The novel "Captain's Peril" (by Shatner if I remember) actually did this quite well, with Picard and Kirk having to solve problems and clashing with their respective styles. I think this could have made for some comedic and effective character scenes had it been done in Generations, instead once they got to Verdiain III there wasn't any time for their characters and frankly you could have put any two characters into those scenes and it would have panned out more or less the same.