I think open world is the one thing I don't want to see again. I know it's very popular with a lot of people, but for me open world and shiny textures and bright light made the game unplayable. I mean, it's all nice seeing your neighbors go about their own yard, but what what use is the open neighborhood when all the sims are someplace else when you visit a lot? I would visit a bar or a park, and all other sims were either working or home sleeping and it was just my sim there. You couldn't talk to anyone because everyone had some place else to go to.
What I would like to see it's ability to place lots of different sizes and to design our own neighbourhoods. And I second the request for a public transport system with buses, trains, ferries and planes.