Is there any benefit to creating a new kingdom out of a part of my realm? I'm playing as Sweden and recently conquered 8/15 parts of the Kingdom of Finland "region"(?) and I can create the Kingdom of Finland. Will this cause more problems than it benefits me?
Also I'm pretty much a complete newb and I'm having serious problems getting my vassals to like me. I have to constantly bash their heads in every few years because they keep rebelling and this is just a cycle that continuously worsens relations. What should I do? I don't imprison without a valid cause, I don't revoke titles without having a proper cause, I don't do anything ruthless to people in my own realm or outside it. I have recently been more lenient on conscription and taxes for my feudal vassals and have always been having the minimum levies for both cities and churches and the taxes have been somewhere in the middle but this doesn't seem to go very far. I know my taxes are fairly heavy and this causes some problems, especially in regards to my feudal vassals, but I can't see why this would make them almost constantly rebel.
And finally, I would say I have a very good grasp of the economical and administrative aspect of the game but the diplomatic side is a terrible headache for me both in regards to within own realm and outside it. Any general tips for a newbie to be good at diplomacy? For example the possibility to inherit other nations/duchies/counties, how to "properly" manage all my children in regards to marriages with other states and so on. Oh and most importantly, how do I get my vassal dukes to approve the person I want as my heir? Since there is always at least one person constantly far below 0 relations I can't improve the laws regarding succession and I still have elected kings, though thankfully I haven't had the kingship pass to an undesireable person yet.