I'd like to be able to make women into councilors under Absolute Cognatic. They can be landed nobles, but not councilors, which doesn't make that much sense to me. Also, why does every single male hate female rulers and female heirs? There should be some kind of limit to that outside of dynasty. I get that the world was sexist in that period, but if a realm is ruled that way, and well, for long enough, I'd think at least some of them would get over it.
It would be nice if there was some bonus to being the child of a universally beloved ruler for vassals not of your dynasty. The fact that the relationships get reset is very strange. If my previous ruler had nearly 100 opinion with all his vassals, there should be some level of transfered respect to the son or daughter, even if it can be lost easily.
Also, it would be interesting to add a 'seduction' option which would allow you to use your intrigue score and their opinion of you to attempt to start a relationship to create a bastard. If you fail there would be a chance that the person would tell other people what you tried to do, and you'd get a penalty of some kind.