Although as you point out the "replayability" is not the main selling point of the Legacy games, but with many of them you can still replay it like a "normal" b

Although as you point out the "replayability" is not the main selling point of the Legacy games, but with many of them you can still replay it like a "normal" board game once you reach the end of the campaign. And you end up with a game that is uniquely yours. I know in Risk Legacy this is possible. There is a really cool Legacy-type game as well (I'm struggling to remember the name, Arcana I think?) where in the Legacy version you basically go through a campaign and develop a character that you can then use as another character to play as in the base game.