This is a good suggestion. Arriving courtiers should be rather diverse but reflect your realm's composition. And you should have the option of simply allowing them to come in; rewarding them with pensions, lands, and/or position at court; or throwing them out. But they will soon be pestering you with their ambitions, their complaints, the lack of land that drove them to seek your generous patronage in the first place.
I'm not sure how court life is going to go, whether there will be EU Rome style factions (I hope so, please Lord Doomdark), but this could complicate things for the better. So your chancellor might want for you to accept someone into court (he is an old Irishman long in your service who wants his 16-year-old nephew to join the court, which is the old cliche) or your bishop might not (like in CK1--milord, this Greek schismatic has no place in our court! I don't care if he does has a military rating of 23--I'm thinking of the Greek expatriates who served the Kings of Sicily as admirals). Then there are your vassals (or your own liege if that applies) that want to foist on you their own useless family members. "Sirrah, get this young whelp of mine blood land, position, and a comely bride." "Please, milord, my youngest son is a bright boy, good at cyphering, but he will inherit nothing from me. Will you take him into your service?" And then, especially if you have ecclesiastical laws amenable to Rome, the Pope will send his proteges your way.
King has already stated on this forum that there will not be Jewish courtiers for instance (though this can be modded in), but the composition of your court should for lords with many vassals reflect your subjects: your vassals will expect to be included on your council, so it might make sense to keep a lot of direct vassals from around your immediate area of authority, and a small brood of fosterlings hopefully.
It is also unclear to me how many untitled folks will be basking in your regal greatness. Beside your own family members, your fosterlings, and courtiers like these, my understanding is that you won't get the thirty or forty idle hangers-on that we had in CK1. And I expect that those that you will get will move on after a pretty short MTTH, and those with positions will hopefully stay more loyal than in CK1. With what a thousand courts going on simultaneously, that's a lot of lazy nobles to keep track of, so I think it will be an improvement for game performance's sake.