This is a very good issue. The Royal Court would normally "come with the land", and the king should choose his advisors between many noblemen, merchants, generals etc. If we could have a list with their talents (like the royal family) and characteristics (like the foreign kings descriptions on the Poltical View), it would be more realistic and much more interesting.
They should also come to age and eventually die or retire, and we could have the option to dismiss or arrest them, not just exiling - exile should be kept as punishment, but a exiled cleric or marshall could very well become a rebel or a bandit (this distinction should be noteworthy too), taking their troops with them. To hire lesser-knights (off the Royal Court limits) as town-marshalls (with smaller armies), emissaries (below Dimplomats), scouts (below Spies, but able to look out other territories), province traders (below kingdom Merchants) would be very good too.
Another big issue is the role of female characters. Regent and Mother Queens were always very important , and their skills should be considered in the absence of the kings, not to mention when the queen is the real ruler (this should be an option too!), and, of course, legendary warriors like Jeanne d'Arc and Matilda di Canossa (both queen and warrior).