if you want everything --include=schema,data,statistics (presumably redundant with the default behavior) if you want schema only --include=schema if you want "everything except schema" --include=data,statistics
Until we add a fourth option, and then it becomes completely ambiguous as to whether you wanted data+statstics, or you not-wanted schema.
except it is perfectly clear that you *asked for* data and statistics, so you get what you asked for. however the user conjures in their heads what they are looking for, the logic is simple, you get what you asked for.
And if someday, for example, there is ever agreement on including role information with normal pg_dump, you add "roles" as an option to be parsed via --include without having to create any new flags.
This is pushing a burden onto our customers for a parsing convenience.
In the UX world, the general pattern is people start to get overwhelmed once you get over a 1/2 dozen options (I think that's based on Miller's law, but might be mis-remembering); we are already at 9 for this use case. So really it is quite the opposite, we'd be reducing the burden on customers by simplifying the interface rather than just throwing out every possible combination and saying "you figure it out".
