I used to play Farmville on Facebook back when it was a relatively new thing. It gets (justifiably) trashed by most gamers but I actually liked it while I was playing it. It didn't have a ton of depth or breadth in terms of strategy but there was a little bit in working out the optimal things to plant at what times (pretty much everything had different costs, rewards, and time to bloom) and I did like visiting other people's farms to see what they were doing. I also am not put off by repetitive tasks for irrelevant rewards... They don't call me 'the Insane' for nothing! I ended up quitting for a few reasons: the novelty wore off, they shifted even more heavily into a 'spam your friends' model, and they removed pigs as a gift option. I used to give everyone a pig every day and was very amused when I'd visit some people who didn't get many gifts... Their farm was full of pigs!
World of Warcraft is adding a farming minigame in Mists of Pandaria that has me pretty excited. Each player gets their own little instanced farm with a house so the demand for player housing has finally been at least partially met. You get to start off planting 4 seeds per day and can get up to planting 16 per day. There are tons of different seeds (19) and you can grow many types of vegetables for cooking along with any crafting materials. (cloth/leather/ore/herbs/motes of harmony) Each day a different thing grows best so there's the potential for planning out the 'right' seed to plant each day. Apparently you can grow trees to plant in the game world ala Glitch (though they only last 3 minutes instead of until killed). There are 10 different NPCs that deal with the farm and you get individual reputation bars with all of them. Including the generic 'Tillers' reputation that gives 11 different things to grind up on the farm! Each of the friends will upgrade your farm in some way when you reach max friendship with them. The only downside I see here is everyone will ultimately get the same upgrades. I think it would be better if individual farms were customized with furniture based on the player choices like in FFXI and I bet that comes down the pipe in a future patch.
It's hard to tell from beta stories but it sounds like farming might actually be a really good way of generating spirits of harmony which are the new BoP crafting item which is used in all sorts of ways and replaces the elemental ingredients from previous expansions. It also sounds like you need a stupidly large number of vegetables for cooking various things so just growing those might make sense too. The ore/herbs can apparently give you a fair number of the rare drops from those as well... I guess the prices of the different things is something to keep an eye on once it all goes live.
You need to be level 90 to really work the farm (Tillers rep only starts being earned from harvesting when you're level 90 for some reason) but you can get started with planting vegetables right at 85. I wonder if it would be worth running farms on alts? I'm guessing no but I guess that remains to be seen as well. I just worry that some of the tedium will creep into it if done on too many characters every day and I really want to max everything on my main (there are achievements!)