I have a RTW coming up (DONE4) ticketed by AA with Avios being accrued on BA. At time of booking this would have generated some 140k Avios (per speedbird.online) but with BA's switch to revenue-based, it will now generate maybe 54k (same source). I'm making a change in routing so presumably it will now be re-ticketed and the new rules will apply.

Are there other OW airlines which still have distance-based earning, and would it be worth it to use one of those for the journey, with a future points transfer back to Avios?

I guess a disadvantage would be that my OW Emerald status would not be shown, but as I'll be flying in Business anyway this is less of an issue.