Nearly all of those ideas are what i would love to see. Especially these two:

Ca seems to be very timid in adding anything which complicates the basic build more units/conquer the world paradigm. The campaign is desperately in need of some added dimensions which complicate the issue and force you to consider more than just conquering your next province on your inexorable way to steamrolling the world.
Please make it more complex. At the moment, RTW is just a case of smash and grab through the world. It's far too easy. Compared to MTW, this is Kid's stuff.

First, I think that in any province which contains two or more factions which are at war, there should be a substantial negative effect on the population, simulating slash and burn by the interloper and foraging by both sides. So I think there should be, say, -10% growth in any province where two or more warring factions are present. Furthermore in the case of siege, there should be an accelerating negative effect - say 10% loss of pop. on first turn, 20% loss on second, 30% loss on third and subsequent turns.
Much more realistic. At the moment, all that happens when an enemy army stands in your province is that the ground goes black, and you have a small dip in your income. And as for your talk on the random events, i also agree with that. Unlike MTW, where events seem to happen every few turns, RTW has a big event only once a game or something.