I've mentioned this before but the last time was at least a year ago, so since I love this topic, I'm going to see if anyone has any fun ideas, again.
If the devs came along and asked me what setting I wanted a future game to have, I would say 'a hobby or apartment garden/farm in the city'.
City gardens take a lot of ingenuity. I love vertical gardening, and if you only have a balcony to grow on, it's practically a must. I think a setting like that would make the game really fresh. You could farm by rooftop garden, balcony garden, community garden, or all of them. Or you could own a small piece of property with your house, or etc. Animals would have to be creative, too, especially if you want more than just a coop or a rabbit hutch...you might have to do some sort of co-op thing. (It has to be admitted that I have not seriously considered the animals as I could do completely without a single animal in the game and be happy to have loads of time to fuss over my peppers and carnations...so I haven't got many good ideas as far as that goes, yet.)
I'd have a blast modifying my game apartment (or house) to have a bay window to plant an indoor herb garden in, and adding trellises and espaliers and hanging baskets and boxes to the balcony, and a few raised beds to the rooftop, and etc. Your apartment building could, perhaps, be your 'town'...or maybe the whole neighbourhood would be your area to explore. I could landscape and garden in the grassy medians on the streets and rent the yards of people who don't use theirs. I'd love part of the game being to fix the neighbourhood up to be really beautiful and friendly...maybe it could win a competition or something.
I think that would be super fun for me, as a setting. What about the rest of you? Got any settings you've had fun imagining? I would love to try a beach garden sometime, too, just for the change of scenery. But it would have to be fantasy based since very little will grow in potentially salty sand. But I don't mind fantasy-based at all, and let's admit it...bokumono farming is not exactly realistic in the first place.