I believe that by "legacy" he meant the legislative achievements of the Democrats while he was in power. He wanted the USA to be a more liberal country. I have not seen any evidence to the contrary.
Well heck.. I am not even American but even I understood that to mean the legacy of GOOD things, the improving attitude of the rest of the world towards America - that people were beginning, again to see America as a sane, civilised, reasoning and reasonable country..
Pity the posterior-wipe prez you now have is undoing all that good work.