Even though I voted for Single Player in a heartbeat, I want to reason why I didn't vote for the other ones.
VR: Never been a fan of it, and The Sims has always been in a "dollhouse style", that we control other characters. This has never been ego-perspective and shouldn't be. To be honest, VR sims as a part of the main series would just kill it for me.
Multiplayer Online:I think multiplayer just wouldn't work in The Sims. The way the game is set up is not comparable with games like Minecraft. How is this supposed to work? Arguing with other players about the house you wanted to buy? Other players constantly annoying you because they want to visit your home so desperately? Don't forget a chat function - it's the worst thing that was ever implemented in online games. I just can't stand online games, too many prepubescent 12 year olds (play/played League of Legends, I know what I'm talking about :D )
Singleplayer Offline - Sandbox:It doesn't have to be completely offline. I actually like the way TS3 handled this - you can choose to play online or offline, but you need to be online to download stuff from the store or exchange. Mix this with the in game gallery from TS4 and it would be perfect for me.
Combination of the above: Like I said, I don't think that things like multiplayer or VR would work in a game like this. It would just eat development time for the things that are really important.
Tl;dr: Just stay with the sandbox single player experience we have. It always worked, why not stick with it? It's not like there won't be any singleplayer games out there in a few years, their demand is still high enough.