Well what I'm personally hoping for is:
-Lifestyle of the wealthy expansion.
I want to see all kinds of wealthy extravagance, give my sims plenty of crazy expensive stuff to spend their millions of money on. Classical furniture and paintings, a new fencing skill with rapiers, a tennis court, more pool items, a helicopter pad, cars, etc.
As for new gameplay, it could add new wealth mechanics such as a millionaire club and can also allow sims to start dirt poor as hobo's without cellphones or anything and work their way up, so also providing new cheap items for that lifestyle.
A new life state could also be added: Genie. A genie would tie in well with these wealth mechanics, like allowing a poor sim to change places with a rich sim or anyone of their choice, wishing for great wealth, etc.
There are several lamps however, and several genies. You can ask all of them the exact same wishes, but it can turn out differently for each of them.
There's a powerful genie who gives greater rewards and greater risks. Wishing for riches might give you millions, but could also flood your sim with enough bills to lose all their money and have most of their stuff taken away to pay for it.
Death is also possible with many negative outcomes with him, as well as growing old, getting sick a long time and other more extreme effects that ruin a sim's life.
Also a crazy genie which gives crazy effects, when wishes succeed it won't be quite what you asked for but his personal interpretation of it and fails can be crazy too. Like you wish for another sim to love your sim, and now that other sim does not just love your sim but is obsessed with them, never leaving them alone. Wish to be rich and he might scramble your traits, claiming to have given you a rich personality.
Another genie could be like this strict old woman who is very judgemental about anything frivolous. Ask for money and you get a piggy bank to save money, or she takes your money claiming you should learn to value it more. The fails of her spells could be less harsh though, more like life lessons or such but won't cause death. One result could however be your sim being made a baby again to redo their life to see if they'll do it better this time.
Could also be a regular genie.
A freed genie or character creation made genie could be of any of these types, they don't grant wishes but all share some powers and each has some unique powers too.
