Your suggestion has the merit of simplicity.
But I am not sure whether it follows through that a place which is important for historical reasons is necessarily therefore interesting or worthwhile to visit.
For instance, for a time Aachen was the centre of the Holy Roman empire, but apart from a small cathedral, there is really very little to see there.
And there would remain the difficulty of weighing the importance of one criteria over another.
Does the fact that Brussels is head of the EC make it more “listworthy” than a second city of less contemporary significance, such as, say St Petersburg?
But very few people would chose to visit Bruussels over St Petersburg…unless they were mentally ill.