I'm hoping we get one of these by early next year, at least. :/ I am not sure what they could be releasing before the end of this calendar year. But (my most wanted right now is Witches, then University Life).
Witches (lots of magic, spells, potions, abilities, being able to make your own potions, all kinds of magic + weaknesses) Good, Neutral, bad, and Evil witches. Modern, Traditional, Vintage, etc types of witches.
University Life (sorority / frat life. Secret societies, pledging (maybe they could do some kind of "dare system" where pledges have to do task in order to get accepted into the house and if they don't, they get turned away); also.. "True legacy" Sims can get accepted into houses, if their parents went to that college / house. So, they could try out for the house, or create their own. I would love to be able to set up rules of the houses and activities that they could do inside the houses with their sorority sisters / fraternity brothers. Then they could throw parties or some kind of get together's that included other houses getting to join in on those activities. I really hope they really focus on the houses / dorms experiences and activities this time around, if they make a University Expansion pack.
Beach themed / scuba diving / expansion pack.
Teen stuff pack, or game pack.
Elder stuff pack.
Generations expansion pack (mid life crisis, preteens, prom, crushes, sleep overs, pillow fights, scary stories / stories, and loads more).
Farming
Hobbies - All kinds of crafts, being able to make clubs and doing hobby interactions / activities. I'm very big on getting more and more activities that Sims can do solo, or in groups.
"Hot Date" / Night Life - Interest - (Sims have things in common, attraction system, dating system - new places to take dates to - new activities. New proposal interactions at booth, or table, or even new ways to propose (I've seen some really sweet ones in real life that could be looked into for ideas), photobooth will be back, but with even more options, can choose how to pose, can add filters, etc). "Online profiles". Ability to go on Double dates.
Pool table. I'd like to see pairs of two being able to play pool. This could be something that they could do on double dates.