I believe you may have mistaken mods for devs. I know many mods hate bots, but J&L if I remember correctly are mildly neutral about them.
The only reason I don't like the idea of being able to easily create large sections of stone or grass or plow is simply because I don't like the idea of being able to use it so easily for harassment but then again you can just use a bot now so the argument is mildly moot.
And I also think when you harvest the purposed crop field you should also replant basically the same way regardless of the plowed/unplowed status of the field, but yes large paving projects are still a pain.