No, liberty works better on large maps, because of the representation and meritocracy. It's specific area of expertise is when you're jammed between Hiawatha and Montezuma with 2 expansion spots and you need to kill at least one of them fast. Then move on, and kill the other, all the while connecting roads, annexing cities. And keep expanding in this fashion.
On continents, especially, huge continents, liberty's admiral is the difference between meeting all civs around t.130 and meeting them all around t.180, which speeds up world's fair significantly, as you might guess, without ever needing astronomy. And world's fair will fuel your domination campaign with tons of happiness from full commerce. World's fair aside, you might end up in the area with lots of luxurious duplicates and tons of strategics. Admiral can sell all that. Or just rush NC at any early date, or Machu, or scientist, etc, etc.
It's a solid tree for places where tradition wouldn't work as good.
Wait, you're saying that you would use your liberty finisher GP to get a crappy admiral? for real? Even if meeting other civs is that big a deal who's to say the admiral doesn't get nailed by a barb ship 2 turns after it spawns? That sounds very crazy to me.