Depends. If they focus on story and character with humour it could work ongoing. If they focus on spoofing Star Trek, they'll run out of jokes very quickly.It might work better as a one-off movie (Galaxy Quest receiving royalties) but as an on going sitcom, the joke could wear thin pretty quickly.
One more thing Seth McFarlane is borrowing from Star Trek, especially Star Trek: The Next Generation, is its optimistic view of the future.
Once upon a time, STAR TREK filled that bill too...I'm not a huge fan of Seth MacFarlane but I am really enjoying The Orville.
I'm tired of serialized television and its demands along with the dark dystopian outlook we see so much of today.
We need some bright and optimistic television to watch --at least I do. The Orville fills the bill.