I'd love to see an online feature in The Sims 4 with an open neighborhood style. Imagine being able to invite personal friends or find new friends online to join your game. Each friend could control their own household within the same neighborhood while I'm playing mine. They could be building or playing on their lot, and we could visit each other's lots seamlessly. Think of it like Minecraft, but in the world of The Sims 4.
But of course, there needs to be a focus on single-player first. The multiplayer mode should be a bonus for those who want it. It would also be cool if a friend could play with you in a single household as well.
I also want to see an in-game mod system, kind of like Steam's Workshop. It could make updating broken mods so much easier after a patch. Additionally, I wish The Sims could get their own launcher. The EA app sucks, and I feel The Sims needs their own dedicated launcher.
What I don't want to see is a separate Sims 4 version for multiplayer. I want the option at the main menu to play single-player or play online. Not sure how it could work if your friends were offline. There would have to be options so you could keep playing even if they were offline. Or options where you could play their household if they are offline. But EA really needs to work with the community before they decide and make any plans final.
However, I worry the current game might not handle this well, especially since I experience simulation lag occasionally, and I own all the DLC except for 6 kits. EA really needs to enhance the game's performance to fully utilize the resources available on high-end gaming systems. For reference, I'm running an AMD Ryzen 9 3900X, 64GB DDR4 RAM, and an Nvidia GeForce RTX 3080.