i also voted to have City Life brought in for additional development, because there is a lot more potential to find in it.
All the apartments could be expanded on with additional floors and more apartment neighbours as well. potentially you can explore the entire apartment tower and everyone within, or half a towers worth of neighbours. no other adjustments need to be made to the game (aside from some routing issues needing to be addressed), but the ability to have more apartments could make City Living potentially the most valuable expansion out there and allows for more dynamics between neighbours above and below. so no longer can you just enjoy yourself in the spire, torenti or fountainview towers any more, now you got to deal with neighbours who will be upset with the noise level.
I'd just love to pack my sims into San Myshuno and create custom apartments for them. Old salt house wouldn't be needed any more and can be converted into a library or something of the like. also the potential to add more lot traits would be nice.