For instance, would it be okay for a user to ask "How is the execution of Charles I in 1649 viewed in modern day Britain?" This seems like a subjective question and not every Briton will have the same view on the topic, but I can understand where the question is coming from. The user may wish to know, for instance, whether the execution is viewed as a 'stain' on British history or a celebrated overthrow of a treasonous monarch.
Good question, and I think Mark's comment is right. Any question along the lines you proposed would invite lots of subjective answers. Your instincts are right that this question would be subjective. I think if a question could be worded in such a way that a valid answer would convey a historical viewpoint for a society, or prevailing viewpoint, that might work.