Right, preference over possible logical consequences of given situations is a strong unifying principle. We can also take physical world to be a certain collection of mathematical structures, possibly heuristically selected based on observations according with being controllable and morally relevant in a tractable way.

The tricky thing is that we are not choosing a structure among some collection of structures (a preferred possible world from a collection of possible worlds), but instead we are choosing which properties a given fixed class of structures will have, or alternatively we are choosing which theories/definitions are consistent or inconsistent, which defined classes of structures exist vs. don't exist. Since the alternatives that are not chosen are therefore made inconsistent, it's not clear how to understand them as meaningful possibilities, they are the mysterious logically impossible possible worlds. And there we have it, the mystery of the domain of preference.