There is a fork, ClassicPress, already. I may spin up a VPS this weekend and try it out.
Replied to Sticking With WP 4.x For Now by Ton Zijlstra (Interdependent Thoughts)
Well, that ‘for now’ was rather short lived. Thinking I was updating a plugin, I accidentally pushed the button to update WP itself. So now I’m at WP5 regardless of my original intentions. Quickly installed the classic editor. My site still works it seems, but it might be some of the plugins actually now don’t. Hopefully I’ll be able to sort things out.