More cabins with 2 bedrooms! Alternately more adjoining rooms. Look at the beach market, plenty of condo's and cottages with multiple rooms. As more and more are families cruise together, the demand for tihs will only increase.
Similarly, I wonder if "suites" of rooms would work. E.g. 4 rooms sharing a common/shared gathering space but with separate bedrooms and baths. We travel with a large extended family, and this is the one thing that we don't have that we have in beach cabins, e.g. an area for us all to gather w/o having to find a public space.