Ok, so I've elevated myself to become Emperor of the Holy Roman Empire (I started out as the count of Wiemar), initiated Gavelkind succession and have started strengthening Crown authority so that I can get primogeniture at some point. Then, my emperor died unexpectedly, and a good third of the empire broke off in revolt, which made sense as I'd just changed the succession laws away from election. Question 1: Is the size and scope of the rebellion due to the inheritance laws being recently changed, or is it something you have to deal with every succession if you have a realm like the HRE?
My second question, which is far more important, is what do I do with all the imprisoned vassals? I'm tempted to go on a massive banishing spree (I even have the King of Bohemia in jail
) and start afresh by assigning people I choose to the titles I don't want for myself. Is this a bad idea? Mainly what I'd like to know is the best way to secure the realm when half the most important nobles are in prison, under your control. Cheers in advance 
My second question, which is far more important, is what do I do with all the imprisoned vassals? I'm tempted to go on a massive banishing spree (I even have the King of Bohemia in jail