I like the idea of being able to customise the exact length of each part if you decide to bend the staircase, that being said, spiral staircases would be amazing!
I'd really love the idea for cafe's to be themed, Like you could choose a bakery, an icecream parlor, a milk bar or a deli, Bring back having to go shopping for food too!
In saying multi purpose, I really wish they'd introduce hotels or motels, In some kind of like vacation pack? Camper vans/Motor homes too, Cafe's and gym's would be great, as would a pool and a gym, or a library and a cafe!
Adding car's and things such as charity car washes (since you can donate to charity) Drive thru movie theater's (for dates) and even camper vans/Motor homes would be such a great idea!