Some may have been mentioned before.
Autofill drop-in boxes for compost, crop dust, scarecrows and seeds. I know that this has not been implemented up until now because there can be more than one kind of seed, and it is planned that there be more then one kind of the other plot additives (so, there is going to be bolder scarecrows?)
Still, it makes sense that if there is only one kind of these items in your bags, the UI should autofill with it.
Also, the top item in a menu is the one that is performed with a double-click. In most cases, this is the next logical action: rake when the plot is unclaimed, seed when the plot needs it, prune during the growth phase, and harvest when the plot is ready for that. But there is one place where the default does not make sense: after seeding. At this point, the plot needs water, and pruning (which is currently what is on top) does not make sense. So shuffle the menu for the correct double-click default during that time.