I agree. I think one reason for those restrictions is that Paradox wants to prevent "exploits" and strange effects. By leveling the playing field, the consequences of those actions are easier to track.
Some examples :
- Seizing land during a war could result in your ennemy having to fight your rebels since an army just popped out of thin air.à
- Provoke rebellions would work the same way
- Allying new people after the war declaration would make declaring war far more a gamble since you could have the opponent suddenly allying a big dog and outnumbering you
- Integrating vassals is already locked when the vassal's capital is occupied, so I'm not sure what is gained by locking it to being in peace...
In my opinion, those hard locks are where Paradox should look like to make new mechanics.
- Maybe the ennemy could negociate with rebels, or the player could negociate to have their support against a common ennemy
- Rebels could have some kind of sense and not revolt (even provoked) when the country is at risk, depending on their type of course
- When you declare war, you could see who your ennemy *could* ally in the next few months, or who would guarantee the country integrity to a point. This would require a rework of CBs and peace deals so that they aren't made in a day
- Integrating vassals should just be unlocked
