To cover cases where people are making judgments about what others should do, I could also extend this summary in a slightly more cumbersome way:
When X judges that Y should Z, X is judging that were she fully informed, she would want Y to Z
This allows X to be incorrect in her judgments (if she wouldn’t want Y to Z when given full information). It allows for others to try to persuade X that her judgment is incorrect (it preserves a role for moral argument). It reduces ‘should’ to mere want (which is arguably simpler). It is, however, a conception of should that is judger-dependent: it could be the case that X correctly judges that Y should Z, while W correctly judges that Y should not Z.
To cover cases where people are making judgments about what others should do, I could also extend this summary in a slightly more cumbersome way:
When X judges that Y should Z, X is judging that were she fully informed, she would want Y to Z
This allows X to be incorrect in her judgments (if she wouldn’t want Y to Z when given full information). It allows for others to try to persuade X that her judgment is incorrect (it preserves a role for moral argument). It reduces ‘should’ to mere want (which is arguably simpler). It is, however, a conception of should that is judger-dependent: it could be the case that X correctly judges that Y should Z, while W correctly judges that Y should not Z.