Exceedingly annoying is working as intended. Unhandy and excruciatingly tedious could also describe the process.

Instead of flattening - pickaxing - flattening - lifting - flattening and so on...I would love a "flatten terrain" tool that would straight up flatten the ground any amount necessary and "add or remove" the required amount of stone from the inventory in the process. Or just remove, by all means, if that would be considered more "balanced".