Putting together an Alliance to fight off an extradimensional threat sounds pretty unique as a series plot for Trek, considering most of the time said Alliances have already been formed. Especially when the folks in question had no power base to begin with. Seeing all that being built up would've been enough to set it apart. It would've been a way of combining TNG and DS9's approaches. Planets of the Week that later come together into a stationary plot.
The whole "Lost in Space" thing just isn't sustainable for more than 2 seasons. Even the VOY writers themselves knew this, which is why when Braga came on he wanted to do new ideas like "Year of Hell" and the 8472 aliens and stuff.