I do not like the subscription model. If Paradox goes sub only I will not be a subscriber. I also cannot see how they can coexist well. I will probably be repeating what others have said but I feel it bears repeating.
I think that these two models (sub and dls) are at odds with each other. With a subscription model you want a constant stream of little updates. You need to show that you are still getting added value for the subscription. The current DLC model talks about larger updates but less often. I am hard pressed to see how you can reach both of these goals. To me that means that you will not satisfy either group.
Personally I feel that fewer-but-larger updates would be better as you would have more time to actually finish a campaign before the rules change again with the next update.
I sort of understand what you mean, but if people don't like the direction the game is taking or they are getting bored / fed up with the lack or quality of new content, they will probably simply cancel their subscription, at least until better content is added. So the incentive for paradox is still there...
The problem occurs when I like the current game but not the latest subscription installment, I cannot stop my subscription and play what I already had.
Another negative for subscription is that is negates the opportunity for offline play (or at least complicates it by needing periodic connections). And Paradox can pull the plug and remove your ability to play. Currently if Paradox disappeared tomorrow I could still play my current catalogue, with a subscription model I wouldn't be able to.
I do pretty much the same thing with World of Warcraft. When a new expansion gets added, I buy the subscription and play for a couple of months to explore it. Then I get bored, cancel the subscription, and stop playing. When a new expansion gets added again, I repeat the cycle.
With an MMO subscription you are getting the value of the game server with all the other people, that is the service it is providing. Since this is primarily a single person game that you run on your own hardware that value is missing, they do not provide a service. So we are back to what do we get for our $x per month that we are spending? The only other option that I see is content. Then if there is a 'pause' in content people will complain (you see that right now on the CK3 forums and there isn't a subscription model yet). Which leads me to the conclusion for subscription model, without a service provided, the best answer is small updates often.
(Another thing that you will note with WoW is that you are actually paying for the new content, the expansion, and then subbing for the game server access.)
As long as both options are there, I don't have problems with it. Regular players will want to buy DLC separately (as paying every month will cost you more), while irregular players will pay only for months they play the game.
And then the irregular player looks back and realizes they spent twice as much as what they would have if they just bought it. This becomes a new player trap if they like the product. If they don't like the product sure they are ahead but that leads me to believe they need a better way to test the product. I think at least a "rent-to-own" methodology of some sort would have to exist to have sub and dlc coexist.
The biggest benefit of a subscription model, in my mind, is that the game can assume you have all the DLC so you can build on the earlier dlc content easier. That doesn't work if subscription isn't the only model. (My cynical side thinks the best benefit for sub provider is the knowledge that subscribers will forget to stop there subscription when not playing so they still get money for no benefit provided. How many people here have some subscription that they haven't used in the last few months that they are still paying as it is on autopay?)
Paradox, please do not try to pretend your product is a service. Paradox, please don't ask me to rent your product.