This is a suggestions for a perk named 'Combine Harvester', it will make the harvest all button into a 'Harvest All & Replant' button that will harvest all currently completed items and replant them based on selection in the seed box.
This should be geared to mid to late game so either gated behind a tower level or relatively expensive gold-wise. The idea is to make getting GM/MM on quick growth crops easier and as QOL when harvesting/replanting over and over for medium growth crops.