I'm not a fan of overnight-insta-healing. I'm also not a fan of the solutions above. I want to slow healing down, not make it hard to track, nor handwave time. However, I'm not super fussed about actual realism either.
My current theory therefore, is to simply halve the values. You regain half your HP during a long rest. You also regain half your hit dice pool.
Simple. Other values can be chosen at the DM's/group's discretion. e.g. 1/4 3/4 whatever.
Note: I'm also a fan of slowing down spell prep to match.