From today’s Live Letter digest:

Housing Updates
We're currently in the final phase of adjustments for housing-related updates, such as increasing the maximum number of furnishings that can be placed, and allowing housing to have interiors which are larger than their exterior appearance.

We still need to perform major optimizations for handling immense amounts of data, so we'd appreciate if you could bear with us a while longer. We will follow up with additional details when we have updates to share.
While I wouldn’t expect to see this in the current patch cycle (7.3x), unless they do a presentation specifically for it, this is the first time the interior size change has been confirmed to be coming alongside the item limit increase, and within this expansion. “Final phase” sounds promising but who knows how much longer a wait we’re in for.

But it does seem like they are holding the item limit to do interior size change at the same time. Twelve please don’t let them be linked! I want a small with more items in it, I don’t want to have to increase interior size to get more items!