Don't you want to start with UHC from a negotiating perspective? Heck, Obama never even pushed super-hard for the public option.
I mean, yes he did? He didn't spend too much time talking about it because he wanted it to actually pass, and he observed (correctly) that if the GOP refused to join it it would become an ongoing cultural conflict. He pushed the Democrats pretty hard on it -- multiple Senators gave their political lives for the ACA as it is. I think it's pretty well-established that Lieberman, who nobody had any leverage over, killed the public option pretty much by himself.
Healthcare seems like more of a policy thing at this point than a politics thing. Hoping for better economic outcomes seems important to me, but politically it's not clear people that benefit from healthcare legislation via coverage (and not via cost) a) appreciate healthcare coverage b) see healthcare cost control explicitly and c) vote.
Hillary gets that I think.
My observation of people who don't like the ACA suggests that the vast majority of them, on both left and right, just don't understand what the ACA does. So I definitely think that politically it's not worth engaging in right now. Give it a few more years, let Medicaid expansion spread to a few more states, let's talk about it in 2020.