FWIW, I checked two websites done with confluence (https://help.nimbleams.com/ & https://help.k15t.com/) and the HTML is not that great either. That’s good news 
Now it doesn’t mean we cannot be better than Confluence on this topic 
Again, I agree this is not our top priority. It’s just about checking if we have some easy idea that we could implement to improve our generated HTML.
BTW, stupid question: should generated HTML be stripped of all white space and new lines? Would that improve browser performances to render it?