I understand why you would want that, but this could become a source of notification spam. And tactical choices like "neighbor ripe for attack" are something you should do instead of the computer. A big part of the game is being attentive on what's happening around you. IMO, ledger information is also part of being attentive, it gives you something to do during peace time.My personal QoL wishlist would be: I'd like more alerts when doing decisions, declaring war, etc.
Basically things like "Hey idiot, you're about to declare war on this country but you have a free rival slot and you could use it against them!"
Also another alert like "Neighbor Ripe for Attack" when all their allies won't answer, they're fifty loans in debt, and their army got stackwiped. If you think that would be unfair, you can already get this information from the ledger and the AI uses that information when deciding to attack you.
Speaking of the ledger, can we finally get troop numbers in either the diplomacy or declare war screen? We have all this information, and more, but we have to do additional clicks for EVERY nation.
About the first thing: instead of such a notification, the free rival slot shouldn't disappear. Or at least I have the feeling that it disappears. After you lose a rival during a war, I've got a feeling that the game doesn't always inform you of new possible rivals after that war.