Very good, I agree with all these removals

. Magistrates - very annoying, Spies - kind of a tabu to me, Core - stupid to always take 50 years no matter the conditions, Sliders - never liked them, good riddance. Agents - It seems there is no more the limit of 5, you start with limit of 1-2 and probably can increase the limit somehow, at least diplo&merch have names and very probably aren't 1 time use, it would be interesting if they could gain traits (like if merchant fails at his trade mission) and be able to dismiss him, though maybe going too far about it.
Though all changes are good only if they will be replaced with better stuff, hope it'll be so.
I see no response about hordes, I pretty much hate the way it is like now, I'm hoping it will be changed at least and no more automatic wars... CoA or flag depending on dynasty would be awesome, but probably too complex to do, it could bring some weird situations... Hope trade rights/leagues remain somehow, and a "Buy province" option would be nice.