I do not believe that Clinton will suddenly turn into a liberal when elected any more than Obama did. There is false hope in that. She has a record of supporting conservative measures in both economics and foreign policy and solid Wall Street support in her Presidential candidacy. Her feminism, at least, somewhat leavens her conservatism. She seems to be Wall Street's Democratic candidate; their hedge if someone like Rubio does not become President.
Sanders, on the other hand, cannot possibly deliver on his policy proposals unless somehow the whole Congress is overturned. I think he knows it, too, and will compromise when push comes to shove. But how will the public react to that? Senators are expected to compromise; Presidents are expected to lead. Still, Sanders, with his 25 years in Congress pushing for incremental reform has a damn good record as a liberal reformer, while Clinton, with much more history as an appointed than elected official, has a poor one.
It may not matter. Foreign policy and domestic immigration policy may dominate both the election and the next Presidency, making all these issues moot. But there is much false hope for liberals. Clinton supporters hope she will turn into an economic liberal, which seems unlikely, and Sanders supporters hope he will somehow be able to get sweeping reforms through a Congress that has charged off a cliff to the right, which also seems unlikely.
Maybe the best possible outcome is for Hillary Clinton to become President, the Republicans to self-destruct, and the Sanders campaign to go on to found a new liberal party.