My favorite EP from TS3 was Generations, so something similar for TS4 would be awesome; the ability to send kids away to boarding school, imaginary friends, bunk beds, more playground equipment, midlife crises for Adults, canes for elders, etc. We already have Parenthood, but I think the two could enhance one another if one was to have both. A supernatural pack adding back a lot of the occults from previous games would be great – fairies, werewolves, genies, and maybe some new ones like elves, gremlins, ogres, etc. I also absolutely loved Into the Future, and a pack like that one would be great. Seeing the future descendants of Sims was really neat, and I liked how I could basically live and work there, and change how bleak or optimistic the future became.
I also think a pack with a cold climate world, sort of the opposite of Sulani, would be really neat. It's not something we've had since the top part of the vacation world in Vacation for TS1. Snowboarding and/or skiing, igloos, maybe even penguins like in TS2, maybe features like sledding, ice fishing and otherwise just permanent access to snow-exclusive actions. I suppose the issue would be what would happen if someone got that pack but not Seasons. I also thought it was really neat how, in TS1, if you had Unleashed installed, the vacation lots would all have pet bowls and beds added so when your pets came on vacation with you, you wouldn't have to worry about them. I don't know if it's possible, but implementing a feature like that for TS4 would be neat.
As for stuff packs (or maybe even just free updates), I'd personally like more clothes for toddlers (I know we already have packs about them, but I still think they lack a lot of variety). A 70s-80s-90's themed pack like TS3 had would be neat, and could capitalize on the 90's nostalgia of late. A pack with farm-themed stuff like SquirrelTail15 mentioned would be awesome, too; adding more plants and maybe livestock like some of the Store items from TS3, some ways to at least partially automate really big gardens so that Sims don't spend the entire day tending it every day.
I doubt these would be made as packs, but in free updates they'd be cool, so I'll include them. I'd also like some more religious themed things – I doubt they'd make it an actual pack, but they added some clothes for Muslims, and so adding stuff for other faiths, like kippot and tallitot for Jewish Sims and so forth, would be cool, plus objects and food for more holidays from different faiths, with maybe even some holiday traditions added for people with Seasons. Also I'd always love more pride stuff so hoping for more in June :lol: