Well, Crusader Kings 3 has been announced at PDXCon -- and CK2 (the base game, anyway) is
free forever. Confirmed features for CK3 so far are vastly improved graphics (obviously), cadet branches, dynasty heads, and "more customization for your ruler and your religion": dynamic heresies, maybe? Sounds like they went into the project rearchitecting systems so they could support things that just weren't feasible to add to CK2.
I'd like to see baronies represented on-map (and a map with Imperator-style detail) and maybe playable landless/adventurer characters, but who knows if we'll get that. It would be interesting to be able to play a noble-in-exile instead of just getting a game over if you lose your titles. Release date is set for 2020 but "game development is hard" so no guarantees.
Hopefully more details in ~15 minutes.
Edit:
First article is out. Sounds... pretty different. Characters level up, and there are skill trees. Custom heresies are confirmed, and yeah, baronies are represented on a map that is "4x larger" than CK2s, while still covering the same amount of geography. Also, every ruler will be playable from the start, though I'm not sure if that includes theocracies. The article also has screenshots of
the map and
one of the skill trees.
Edit 2: So, from the post-announcement interview, there was mention of a few interesting new features. "Secrets" (if you murder someone, even if no one else knows, it becomes a secret that's tracked and can presumably be leaked) which you can use to blackmail characters, and if you have a secret on your liege he can't revoke your title. Merchant republics are cut completely (which also implies no theocracies). The genetics system has been completely redesigned: expect Habsburg jaws with enough inbreeding. They aren't importing the CK2 events; everything is custom. Nomads aren't in, but tribes are. They're approaching CK3 with a much larger focus on the RPG mechanics. We're full Machiavelli, now: you can rule through fear instead of just love. (No word on love
and fear, but it seems likely.)