Barry Goldwater remains (at least nominally) one of the main ideological forefathers of the modern GOP, so I think he wouldn't mind his legacy too much
Going back the past few elections, and excluding HRC, I feel most bad for Gore. The dude came within the tiniest sliver of winning the Presidency, won the most votes, and if the deck weren't stacked against him in Florida and the Supreme Court he probably would have won (Florida disenfranchised a huge number of Democratic votes thanks to their felony disenfranchisement, and there's a lot of very shady stuff that went down around the potential recounts). And he watched the guy he lost to fuck up both America and the world spectacularly, with Bush and his inner circle almost singlehandedly ending the "end of history" era of post cold-war prosperity