Interesting question. I can't make up my mind and narrow it down to three. For me the best updates were
- Toddlers: the game just didn't feel complete enough without them. This was the update that made me move on from sims 2 and 3 to sims 4
- Bookends and bed upgrades: a rediculously small update but I am using these features constantly. Before this update you needed big bookcases to read, now just a few books on a desk or mantelpiece suffice. Every bed gets upgraded. It is not a major update but I want to mention it because this update is often overlooked while it really improved my game.
- Change occult status in CAS. This used to be such a hassle before this update.
Honorable mentions for the copy outfits in CAS, terraintools and the combination of modular stairs with platforms.
