Given the fairly massive overhauls of a bunch of aspects of the game, it seems safe to assume that the initial release will have plenty of bugs to iron out in a hotfix or possibly several, which essentially rules out anything this year (even if they were somehow ready to release it, Imperator's status is already precarious enough I doubt they want the old CK2 levy bug/Stellaris MegaCorp issue of a broken release sitting there unfixed over break, with the incumbent bad PR).
For those counting dev diaries, note that we still know almost nothing about Vitruvius (which should be good for a couple of DDs; if nothing else they can have one talking about the existing Great Wonders), have 3 more Diadochi trees to go through (assuming they are limiting themselves to just the 5 Diadochi rulers), and can be fairly confident that the new levy/legion system means they'll have to make at least some changes to pops/manpower (potentially another DD in itself), with room for other miscellaneous bits and pieces DDs and maybe another graphical DD if they want to do that as a separate one. And remember that Dev Diaries will probably go on hiatus over the holidays.