A few questions:
1. I had a feeling the 100% coalition warscore thing wouldn't last as it was pretty ridiculous. That said, what DOES push it to 100% in a coalition war? Is it 100% on WL after 5 years (like all other wars), or only by occupying 100% of all coalition provinces? I'm interested in seeing how that join logic works in practice.
2. Do subjects core at negative stability? Has their tendency to simply stop converting province religions they can convert easily been fixed?
I'm not a big fan of "primitives can't build ships", because it's the kind of setup that will too greatly expose natives to screwjobs from blind colonial conquest. Once you actually border a nation it's fine, but in the current patch colonial conquest CB AIs will sit on wars even at high war scores and refuse to 1) make demands 2) take suggestions for peace 3) accept anything in the peace deal screen, even 100% worth. Unless something has changed there is going to be a little too much luck element in "screwed by CC at random before you can react" going on IMO, though I suppose native councils experienced that to a degree already and they are better than other new world starts in 1.9 so maybe I'm not picturing how it will progress properly.
Overall, unless something hidden is going on, this is easily the least controversial/surprising set of patch notes accompanying a DLC I've seen since I got the game. There are quite a number of objective improvements, some "wait and sees", and only a few concerns. If all of this is accompanying subject nations finally working, color me pleasantly surprised.