Personally: my feeling is that if you took Medicare as it is today (sans dental, vision, etc.) with its 80% coverage and expanded that coverage to everyone, we as a nation would still be better off by a country mile. I am okay with a role for secondary insurance, as long as it includes a standardized set of supplemental plans, like what exists today. To me, this is somewhere where you can compromise and appease the diehard capitalists, and doctors who want to charge a premium above Medicare rates. A robust secondary market allows for some flexibility. What I would love to see is the complete elimination of Medicare Advantage plans. Those are a gyp. So if Kamala Harris is fine with something like this, I won't be offended. Would it be nicer to have expanded Medicare, including dental and vision? Yes. But if there is room to compromise, this is the first way that I would find acceptable.
I'm not okay with merely propping up the ACA. The ACA still sucks. I have a subsidy but I consider this to only be a catastrophic plan because the deductible is so high that I don't use it beyond the bare minimum. If I had traditional Medicare, it would be better and more accessible because I could afford the lower deductible and then deal with the coinsurance as needed. And depending on the cost, I perhaps would get a supplement.