We have a lot of what older Sims games used to have in terms of expansions in TS4 now, but there are still a few big expansions left that haven't been added yet, that I would love to see created before EA moves on to TS5. I'm going to list off old expansions that haven't been brought back to TS4 yet
(even after 8~9 years of this game being out).Sims 3: Generations
In an old interview
(iirc it was an interview of Lyndsay), she said EA/Maxis would prefer to split family content up over various game packs rather than making one big EP for it. So far we've gotten Parenthood GP
(which is more about the parents' interacting with their kid and teaching them values and doesn't really add a lot of new activities for children to do), Kids Room Stuff, Toddler Stuff, and now the High School Years EP. I don't mind if this content gets broken up personally, but if that's the way it's gonna be done I'd like to see a pack for each life stage. The new infant update will probably be similar to Toddlers, where they will barely have any clothes or things until a future paid pack release comes out. So IMO I'd really like to see a lot more content made for kids, toddlers, and infants. I know a lot of others are asking for Elder-specific content as well. And I think a lot of them are asking about content that makes us think of our grandparents, who grew up in the 40s~50s, and the type of styles they liked to wear and what we remember them looking like and the activities we did with our grandparents, rather than what's trending among old people in the current decade. So more of that would be nice, please~
Sims 3: Supernatural
We're almost there! This one they are 100% splitting up into multiple game packs. We're only missing Fairies now. After we get a Fairy GP we'll at least have the occult squad that came out with the Supernatural pack. However, occults from other old packs that still haven't been made also include: genies, zombies, mummies, imaginary friends, unicorns, and real plantsims as an actual occult life state and not just a temporary moodlet.
On that note, we still need horses as well. And cars. And burglars!
The Sims Medieval
A spin-off game of Sims 3, but I'd really like to see a Medieval expansion pack made for Sims 4. There is so much TS4 medieval-themed custom content being made all the time. Most people that love the occults in Sims 3 also loved Sims Medieval. This would also be a great pack to bring back the baby dragons that were in the Sims 3 Dragon Valley world DLC and Sims 1 Makin' Magic. Or knowing EA, sell the dragons in a kit after the Medieval EP releases. I just want to have princes and princesses going on adventures in medieval times and being able to create my Dungeons and Dragons characters and actually use EA-created assets instead of entirely relying on custom content for this. And for re-creating season 8 of Game of Thrones and doing it much better than the show... This would also be really nice for anyone that's doing the Ultimate Decades Challenge or the History Challenge!
Also on that note, a stuff pack or kit for every 1900's decade would be amazing as well!
Sims 2: FreeTime
I know we got that one knitting pack, and in the community vote that stuff pack had there were other options like pottery and some other hobby related things. I think this would do better as a game pack rather than a full on expansion, but it would be really nice to have more hobbies added to the game. Also a bands pack would be nice as well.
Sims 3: Into the Future
I'd love a futuristic sci-fi time travel pack. And no, as much as I love Star Wars, the Journey to Batuu pack doesn't fill that need for me. I want sims-universe sci-fi where my sims can travel in time and meet their descendants. And lots more futuristic tech to give to our alien sims! Though, while this one would be nice to have, I wouldn't be too upset if they never made a pack like this. Between Get to Work, Get Famous, StrangerVille, and Batuu, we do have a fairly decent amount of sci-fi content. It just sucks that you have to buy 4 packs to make yourself a sci-fi save.
The Sims: Livin' Large
A lot of the Livin' Large EP has actually been added to TS4 through base game updates and various packs
(tragic clown, chemistry, telescopes + alien abductions, servo, grim reaper, santa/father winter) however there are a few iconic sims things left that we haven't yet gotten. Those would be: the Vibromatic Heart Bed
(and while we're talking about that you can't forget the Sims 2 Love Tub, hot tubs are base game now, you've got no reason not to make it!), the Slacker career, and a crystal ball
(i know we have one that's for seances, but it'd be nice to have a crystal ball that's for fortune telling, and an interactive tarot deck to go with it). This is also the pack that first introduced genies and zombies to the game. We could also use a Las Vegas style world, which is one of the building styles this pack had that we don't have yet! Honestly, most of what's left of this EP could be introduced to TS4 through kits, if they ever bothered to make another gamplay kit...
Also, could we get Funky the Snowman in an SDX drop, please? The little dancing snowman from Sims 2 is a personal favorite of mine

Comments
- Sims 2 freetime: sewing, pottery, the car to work on,... I miss those activities
- Sims 2 bon voyage particularly for the hotels. In sims 2 we could see the inside of hotels and build our own. I would like hotels to return as actual lots, preferably with the option to run them as well. We already have a tropical world and a winter vacation neighborhood in sims 4 so it is not so much needed for destinations.
- Sims 3 into the future: the futuristic world is awesome. I enjoyed seeing how there were technological improvements in various everyday things. I would also like the return of plumbots. Their customisation was amazing, especially with the current servos that only have one shape. As mentioned in the first post this should be set in the sims universe, not in as part of a 3rd party franchise like star wars.
- Sims medieval : not exactly an EP but a medieval environment would be great. Perhaps this could be done as a sort of time travel pack. A two parter with one pack into the future and one for the medieval time. But each time would need an EP to be done properly
Other tidbits I would love to see return but not necessarily in the same pack combination as before
- real permanent plantsims like we had in sims 2 seasons and Sims 3 University
- ticket machine from Sims 2 open for business. This is a machine to make visitors pay an entry fee on your business lot so you can run a community lot that is not a store
- baby dragons from Sims 1 making magic or the sims 3 store
Oh, I completely forgot about hotels! I completely agree with you! Perhaps that could be a similar game pack to Dine Out (hopefully not broken/buggy tho...) where it comes with just hotel lots to place anywhere you want rather than coming with a world. It'd also give them more time to focus on making the gameplay really good and customizable if they don't have to put resources into make a world for a Hotels GP.
Medieval
Into The Future
Yus! Another fantasy & sci-fi fan
So happy at least one of my must-haves is being released this year!
I want a Sims 4 version of The Sims Magic Town since the Magic Realm is lacking. They could introduce fairies in it
Yes, please. I also wish it was easier to adapt the existing magic world. I know there's a way but I think it's awkward so I never do it.
I'm honestly surprised that fairies weren't put into Cottage Living, though they would be better and more in-depth if they made a Game Pack for them. How would they do a new secret fairy world that's not too similar to Magic Realm or Henford, though?
If they end up being a side-occult of an EP like mermaids were, then I think they'd fit well into a Medieval Expansion Pack. I'd rather them be separate packs but having 2-in-1 is better than having neither or only one imo.
I 100% agree!
Bon Voyage
Medieval
Roaring Heights- not a pack but basically it was a pack.
Also- horses and festival lots.