Multi level foundation update would be needed unless we were forced to use detached garages only. That would be a big base game update just like basements and other build mode patches over the years. Would be for when a new EP comes no doubt too. Wouldn't make sense to include something that huge for a SP or GP.
Also cars would be a part of the EP. Which we would get around November/December as is tradition. June for EP1 and November/December for EP2. 2 EPs per year is what we've been getting for a while now.
If cars came back they better be like Sims 2 and not 3. 3 did many things right, but cars were awful. The only good vehicles were the mopeds, bikes, and saucer. I want to sit in them, listen to music, make out and woohoo in it as well.