Villagers could fill in 1 block holes, break raised blocks blocking the path, turn grass blocks into path blocks when surrounded by 3 other path blocks.

Villagers could fill in 1 block holes
You mean non-road right?

Break raised blocks blocking the path,
This is tricky. Villagers have an upward bias to fix roads.

Turn grass blocks into path
blocks when surrounded by 3 other path blocks. I think they are supposed to do this now. Got a world seed/x,y,z where this fails?

I'll look at path fixing when I'm in this time. See if there are areas for improvement.