I have a work associate (we are all self employed) that bought 1 of the only 2 policies that was available to us in Washington state at the time. She ended up with cancer and the ensuing costs sucked up all the benefits under the policy, took about another million or so, then bankrupted her family. In our system, having the best insurance couldn't help her from financial ruin. The kicker is, she was told that there was no hope, but the care ended up saving her.
So, how do we keep good care but keep people from social ruin and protect the poor. I think the best choice would be to start with some kind of government provided insurance with a deductible based off income and wealth. For the very poor, it might be a $5 co-pay and go up. This provides incentive to not over use it for the very poor and protects the very rich. Private insurance could still exist, as they could provide the basic insurance against the deductable needed for the middle income or higher wage earners. Not much different then it is now, but provides a means for everyone to get insurance and protects people from financial ruin if a catastrophic illness occurs.
An immigrant friend of mine got a real good deal on a car a few years ago. He was a little skeptical so he asked the owner why they were selling it. The seller told him that his wife had cancer and they needed the money fast to continue her treatment and that he was selling off whatever he could. He looked at me, and said " I thought America was supposed to be the greatest nation in the world. Even in my third world country we had a better system."