Totally agree, there is not a single moment to rest, gather troops or go to your castle.
I think that, in order to fix this, the AI should be seriously modified both in the campain map and during a battle/siege. They are agresive and stupid as it is right now. They raid every village and siege every town constantly with +600 armies and then, during most sieges they get stucked on the walls and do nothing during battle.