You mean having regions generate resources, and the realms only being able to use those resources if they own the region? That would surely drive realms toward taking strategic regions due to the resources they provide.
While it sounds fun and realistic, I doubt it would be. It would be yet another layer of complexity on the game that could go wrong since balancing such a system would be a nightmare.
Seriously, the game used to be dead simple as far as getting started and keeping things running went. It was fun and care free. Then we got the push towards duchies, oaths, the new tax system, various realism addition that, while realistic, didn't really make the game much more fun.
You've pushed responsibilities on people who generally don't seem to want to deal with them(food being a major one with regard to lords).
You've pushed the responsibility of getting an income on the new players instead of it being automatic like it used to be. The new estate system won't fix that issue as far as I can see though it might mitigate it..maybe.
The push for duchies to be prominent seems to be pretty much a failure to me. They're too small units and just about anyone will choose their realm over the duchy because it is the realm that provides all the fun and atmosphere in 99% of the cases. Start pushing for the realm as a team again since that actually has a chance of working.
There are lots of these things that eat away at players fun. Look back to how the game worked in 2004-2005 or so and learn from that. I suppose what I'm trying to say is..instead of further making the game complex, simplify instead, see how the players actually play the game and try to support that instead of trying to force them play a certain way.
