I have to be honest, I do kind of hope that we get solid rules for operating an entire kingdom.
I also hope they're in an expansion book. I'd HATE for them to be core. Any decent treatment of them is going to need so much space that fitting them into the core rules would be impossible without neutering them. Plus... they're kind of plot elements, not mechanical elements. I mean, they have mechanical aspects, yes... but I can't help but think that operating a kingdom belongs in the optional expansion books instead of in the core rules, simply based on how often people operate kingdoms. Maybe DMG2 or 3, or a book written specifically for this purpose. Ideally the specific book.
What I'd specifically like to see would be:
1. Premade castles for those who don't want to make their own.
2. Detailed rules on making your own if you do. I mean old school, detail every last window. Don't try to sell me some dumb combat system tacked on to it, though. I'm looking at you, Rules Cyclopedia.
3. DM ADVICE! LOTS OF IT!
3a. Specifically, ways to handle the inevitable disparities in attention that crop up when one PC is Pharoah, and the other is his best friend the ratcatcher's apprentice he met when he ranaway as a child. I'm well aware that this is a solvable issue, please don't preach to me about that, that's why I'm asking for professionally written advice on the subject.
3b. Also DM advice on ways to let the PCs get away from their obligations from time to time, and adventure a bit.
3c. Advice on using skill challenges to handle things like wars. Large scale skill challenges. As in, negotiate a military alliance with the Duke before the orcs arrive, one success. Complete construction of the upgraded fortifications on time, one success. Prevent the assassination of the captain of the guard, one success. Fail to ambush the orc's siege weaponry while it was being transported by sea, one failure. Sneak a strike force into the orc camp to BURN the siege weaponry, cancel that failure. You get the idea.
What I'm not looking for, and actively hope not to find:
1. Rules that connect plot elements like being a prince or leading an army with PC level. If your 12 year old level 1 PC is Pharoah and in command of a million soldiers and the greatest fleet the land has ever known, then that's that. Don't try to tell me that I have to be level X before I can have a court magician. That's a plot matter.
2. Rules that prevent me from handwaving micromanagement issues. I suppose there's someone out there who wants to analyze crop growth and weather patterns and road capacity, and if those rules are to exist anywhere this would be the book for it, but please, PLEASE I want those to be ignorable by the rest of us. I should be able to let a relatively casual, inexperienced player be a princess and in charge of an estate or even an entire realm, without sending her to princess-school first.