Wow -- excellent and well-thought out suggestions. I'd love to see most of these if there is to be a PT2 (and some would work well with FT2, if that were to happen as well).

Was thinking, though, that a compromise for being able to change the price of a plant in the Nursery is to have a "Sale" button -- clicking this button would automatically put all plants still unsold on sale and lower their price (by 20%, say). Might be helpful for clearing out those last couple of plants that never seem to sell, and getting rid of the ones that you can't seem to prune right.