I doubt that they'll make playable adventurers. Maybe playable theocracies? Whatever it is, it should be something meaty, the last DLC was in March, was it not?
Playable theocracies seems highly unlikely. Most Christian priesthoods of that era require vows of celibacy. This is a dynasty simulator, not a nation simulator. Theocracies aren't going to happen barring a major shift in gameplay.
I still want my theocracy DLC with your "dynasty" being your Order, like the Benedictine monks, and your "heirs" are people sent to your theocracy to be educated, like the second sons of kings and such. Bascially, you initiate people into your order, and that adds a second "dynasty" tag to their profile sheet.
And new Orders are created when you create a new county-or-higher level theocracy, named after either a famously pious member of your house (if you make one of your dynasty the first bishop) or named after the first dude (if random/not important house). Lords from all over the realm or world-of-that-religion would send their sons or daughters to be educated, and depending on what religion it is (like Fraticelli has women bishops) then the sons or daughters become the "Heirs" to the bishopric. You would also be able to bribe a king into sending a particularly lucrative son to your order.
Succession would be like Republics, i.e. voted on by the clergy, not guaranteed that you would win but that's okay, you'll still have things to do in your Order House. I'm not sure what game-play the theocracies would have to differentiate them from republics and feudal holdings, like what you can do besides conquer land. All I thought of was how to make it still the same game, i.e. keep your heirs alive and don't lose the land or yer fucked.