You know, I actually hadn't thought of that. If regional incomes could be effectively combined, taking those badlands could actually be worthwhile. And I can just imagine how fun it would be to be duke of the badlands and have no knights or lords: you wander around unruly, depopulated lands, holding court in empty estates, collecting inefficient taxes... it'd be fun from an RP perspective.
(which does not justify temporary lordships, just fleshing out egamma's suggestion that there should be some mechanism for doing this)
And with the new ability to give specific names to duchies it could end up being a pretty cool RP thing, for sure.
