Yes, I agree half finished refactors are bad. But I think with AI the timing is a bit different now so the best plan changes. I.e. AI can finish various steps in generating the new version and transitioning to the new version much faster than people could in the past. So you are unlikely to end up with lots of half finished refactors because AI can finish them fast.

The bigger problem now is handling the AI mistakes and failures, not slogging through all the steps of a refactor. So having a full and complete ready to go fallback version with like Blue / Green deploys might be really helpful. But to do that you need discrete versions, not digging through diffs to find the problem and redeploy.

But this is all just a theory I haven't tested right now.