So you changed the entire history of Star Trek!!!
Actually pretty much just the name of the main ship, though that would have a little impact on the tone of the show I guess.
"Space... the final frontier... these are the voyages of the starship Lexington. Her five year mission..."
Now Space Battleship Yamato is greatly changed ITTL.
The true sadness, however, is that since virtually everyone involved with the show was born after the PoD, there won't be a Firefly ITTL. :-(