Aside from the AI the UI remains the most serious flaw of this game in my opinion. I can't tell you the great percentage of my time spent click to the correct courtiers for simple actions such as marriage, advisor selection etc. My guess is they (Paradox) only thought that the "normal court" would contain around 50 people at max, but that is much an insecure situation which you would not try to sustain in a longer game. Generally, I try to have more people (mostly relatives) than I'd ever need because those courtiers might just catch an illness at any time, even at the most inappropiate moment.