IMO basic problem lies in fact that we're still trying to edit hierarchical tree structures of HTML and CSS/SCSS as a plain text instead of editing underlying tree structure.
I think that good HTML/CSS editor should operate on tree and every CSS rule and every property should be object rather than plain text. That would allow to more natural editing and faster code modification/refactoring (I am frontend developer but I hate writing CSS/HTML by hand. It feels like using punch cards... Better editor could allow to do things faster and more effective).
I was looking for structural (and projectional) editor for HTML/CSS and didn't find any. So I started making my own (here is prototype: https://www.youtube.com/watch?v=yRwx09bAT08 )