My problem with the Paradox model is that it results in a very fragmented audience. They introduce core game mechanics and other important changes in DLCs. If you skip a pack, then you aren't just missing out on flavor for a small number of countries; you're missing out on important game mechanics. The next DLC can't rely on those game mechanics, though, because some players won't have them available. Keep doing that for a few years and you have a very complicated game with far too many different variants to support and a whole lot of DLC that doesn't interact with the rest of the DLC.
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While I fully agree wthat DLC-locking features being is bad for exactly those reasons, it has to be said that whether it's true for Paradox games depends heavily on the GSG you are loooking at
CK3 is really problematic and my worst offender here: A big share of its deeper mechanics is DLC-locked and many of them suffer from being orphaned. They also tend to end up abandoned, as later patches only rarely touch them. One Proud Bavarian hit for the nail on this in one of his last vids: It feels more and more like a theme park with independent attractions of varying quality...and the content is more and more attractions getting added. For me a point has been reached that I'm unsure if I will get future DLC anymore.
Vic3 is the complete opposite: Especially the latest patches brought groundbreaking changes to the base game you can enjoy without the accompanying DLC (which mainly give flavour content to certain ares). In terms of features, only some minor ones are DLC locked or you might gain extra choices when having the DLC. And if you take e.g. Agitators as old DLC-feature, you never have the feeling that they bite in any way with new content - they just fit in a big coherent picture the team behind seems to have.
HoI4 sits somewhere in the middle: Some of the big stuff is free, others things end up in the DLC. At least the latter work in principle together; however in reality, often too many bugs interfer with a flawless experience. A bonus point can be given for a delayed integration of some DLC in the base game (I'm aware that some people don't like that move, but I see it as positive for the sake of getting a better game)
IR never matured enough for afull picture, but followed on its short journey -sadly with lower sucess- the Vic3 route in terms of patch/DLC-content ratio.
Can't talk about EU4 or Stellaris, as I haven't played them.
EU5 however was marketed to go full blown in the Vic3 direction of packing all big mechanics in the base game or free patches later. Given that promise (and my experience with IR...yes, they abandoned it...but I got that much fun out of the hgame, it introduced my into the world of pdx gsg and I still play it with the Invictus mod), I didn't hesitate to order the Premium Edition.