In fact, they were not designed at all!
Perhaps not in the HRE, but that's arguably why the HRE had trouble getting off its ass during most of the middle ages - the central government (Emperor) couldn't do anything about it. The BM parallel would be efficiency. The Germans had a lot of regions but low efficiency so they couldn't get as much out of them economically or politically.
In France and England you had more of a connection between a duchy and a place. Still, you're right that the personal nature of the titles probably made someone realize "wow, this is a really terrible way of administering a country," but that is why feudalism ended - until it did, a Duchy was an administrative unit just because the Duke was the guy who got the administer the thing.
