The game is basically ruined. Worst 150$ I ever spent. Power projection rivaling is broken for large nations, vassal annexing and thus nations that start with vassals were massively nerfed. Regardless of the really nice things they added, the major systems of the game have been so broken that there is almost nothing they can do to fix them short of rollbacks.
Also, I hate to add this, but how on earth did you spend $150 on EU4 when the main game and 2 expansions only cost a total of $65, and the rest of the DLC only costs roughly 30 bucks (ignoring the 2 books) and is all cosmetic anyway.
Oh well, I will state as I always do: give Paradox time to patch some of the balancing errors that they always introduce in primary patches.
On nations starting with vassals: Unless that nation starts with a giant vassal, then most of what I've heard is that annexations are ridiculously easy. And to my knowledge, in no case is there a vassal that is large enough to be crazy. Now, if you are complaining about the continuous string of nerfs to diplo-annexing created vassals, then I can see where you are coming from more, though I still think that the technique had to have some tangible costs.
The only 2 major issues I've seen with this patch is the messed up force PU AE and that rebels are kind of ridiculous at the moment.