Again, how would you implement the possibility to have children? Skipping whole years of in-game time to see the results? Well, yeah, that may work in Crusader Kings, but, once again, creates a whole new heap of problems in M&B style of game. The whole point of the game is to become medieval/ancient/whatever, depending on mod you're using, person-thingy, living his/her/its extremely eventful life in appropriate times. Running around, swinging your sword, that kind of thing.
I agree, it would be fun to have game that while zoomed out completely is Crusader Kings, when zoomed in a bit is Total War and have additional switch to run around the battlefield M&B style. But nor is such game feasible project, neither would it be good M&B game.
About the battles, I agree there needs to be some kind of battle plan feature and even more important a reason for using it (i.e. AI that actually isn't just blobbing around). But for being in-combat itself, I much prefer the restricted abilities to move your troops around. People like to point out that lords of Calradia spend their spare time surfing the web, to access instant knowledge to where each of them is, but radio operator attached to every unit in Total War games doesn't bother anyone. I like the most system from Slitherine's TW-esque games, where you spend lots of time planning before battle, but when it is on, you have access to only three commands (charge, rally and flee) and that's it.
Ideally, I'd like to see, as I've mentioned in different threads already, ability to have dedicated "sergeants" that your units form around, verily in spirit of tEatRC standard bearers. This way you could order them around with those few "simple" commands like follow, hold position and alike.