Yeah the way Paradox does DLCs is - free content is balance, system reworks, adding more flavor to the world, etc. paid (DLC) stuff is basically new content: ie, new game systems, more story, etc. Each time a DLC comes out, everyone gets something, and those that want to expand the content from the base game can do so by purchasing the DLC.
I actually like the way Paradox handles their games from a consumer standpoint, though a lot of people are critical of it. You get to decide on each DLC if you want it or not, and the game is fully functional (though, might be a little sparse on content) with just the base game.
I think where Paradox could be better though, is packaging all of their old DLC (2+ years old) for a decent price. Like getting into EU4 likely costs a few hundred bucks, to get every functional content DLC for example, when it should only cost like, 100 or so bucks (base game + last 2 DLCs or something + gold pack that includes all DLC 2+ years old or something).
Edit - so in regards to Cherryh, a lot of the updates we've seen from Paradox are actually balance changes (which are free). Like both the hyper-lane rework and the fleet designer rework both look like free content to me