There are many subjective improvements and suggestions, I'd make, but just want to state one major annoyance, that should be repeated over and over until it's changed.
STOP THE MODAL POPUPS
Specifically, war participant notifications, at war declaration.
Create a news scroll area, for information that just needs to be seen, without having to stop game play.
I dread declaring war, and the inevitable stream of constant popups for the next few minutes. This is the exact time where you want fewest distractions. As hostilities start you are monitoring progress and being distracted and taken out of it. I don't care that Guyana is joining the war with their one division. In general software UI, a Modal dialog box where you need to click Ok, is only required where it will affect your next action. None of this information requires stopping the game basically. We already know that the countries from the enemy faction will be joining.
On that note.. for events that matter, like when there's in invasion on my land far off area of focus.. there is not a peep. I can lose multiple provinces without knowing, yet they force me to acknowledge already expected information.
So, just needed to rant.
Other that this which while won't stop me from playing the game is super annoying.
I know in NSB, they will be giving an option to lessen these messages, so hopefully it will be smoothly playable finally.