Uhhh, if you beat Darnus Hard Mode (The "final" boss of XIV 1.0), you get his earrings which are pretty nice. Obviously can't get them any more, but you don't need to be Legacy to get them.

Also, Goobbues are Version 1.0 only, but again, don't need to be legacy for that either.

Legacy members get a unique Chocobo for version 2.0.

There's nothing from completing the 1.0 story that Legacy gets over non-legacy. (That I know of)