I sure hope something like that would be implemented. Rather than Japan knocking down ming by itself it has to use alliances from countries like vietnam and korea to form a sizable force to bring down China, since I can't really think of another country in SP you need any real help with bringing down. It would at any rate give small nations who formerly had no chance to beat the foes aka byzantium to form up coalations with countries like the mamluqs, qq serbia hungary and so on to take down the ottomans, since it was in everyone's interest to stop the Ottomans. I am actually kind of surprised nothing of that sort happened, maybe it was due to the Hungarian-Austro-Polish failure to bring down the ottomans and that the byzantine were too far away from the Mamluks to make a deal or that the mameluks were busy with QQ? Anyways, it should definitely give countries like wallachia serbia and the byzantine a chance for a last ditch desperate attempt to stop the ottomans from total control of the region. It should also be so that the coalations can only be formed if the target country is almost bigger than all countries surrounding it combined in terms of military force so that people don't use coalations as a way to prevent anything from growing, but more as an attempt to check big blobs that weren't historical (with exception to France end game cus Napoleon)
Also, the favor system is broken because if you lose to much trust then you will NEVER be able to ally that country again. Not saying it isn't better than what we had before when we could ally pretty much anyone and you would always profit from starting wars first, but not everyone has to like eachother to have a common enemy. Just cus the ottomans don't have AE (Which is pretty broken for AI) doesn't mean they shouldn't be able to form such coalations.
Honestly, I am just so tired of once blobbing as sweden of pretty much being "Safe" for the rest of the game because I keep an eye on my AE, but honestly if you look at a map then a lot of countries surrounding me (unless they are allies or have good opinion) would want to stop me due to fear of being annexed. Whenever I see countries like France or Ming or even Austria blob uncontrollably then it hurts my feelings. It's like the AI doesn't seem to give a toss about the fact that they are next.
Coalations war definitely shouldn't be about "Profiting", but to prevent total control. Since coalation wars wouldn't be profitable, they should only be preferably over "convential profitering expansion wars" when the target is way too big for that country alone to handle, and that country should actively seek coalation allies who are also smaller than the targeted blob itself. It could also take into accounts things like expanding outside your state to prevent "ugly aggressive cancer blobs" who just go a little here and there. Not a "Have to" but it would really make the map clean and "historical", which I think is something worth striving for. This would also make the players and AI more keen to keep allies as it expands, keep itself to states and not random regions here and there, and also make it more worth to increase the state's development rather than amount of provinces. AE could be like an opinion buff which would make others more keen on joining the coalation by their free will rather than always joining a coalation automatically when someone grows to big. This is because the player can always watch how much AE he incurs and how likely it is other countries will form coalations against him, therefor leading to the player never expanding beyond that AE threshold. Now the Player (And the AI hopefully) would have to take into consideration of how the opinion of surrounding countries are of it and not just how much AE he has incurred. Sure, relations were important aswell, but now people might just join not because they are furious but simply because they are anxious, which would prevent big blobs without good diplomacy and state development. Since it is always cheaper to take provinces than to develop your country, I end up like the Roman Empire or even Japan during world war two when Manchuria is better developed than Mainland Japan itself, and it makes you wonder how the citizens feel living in a country that has worse living standards than the countries being conquered.
In short, Amount of provinces, military skill (Since that is important too), Maybe the size of your army to a degree and AE could affect how more "Organized" Coalations could be formed.
A country can't really be called EVIL CONQUERER if he focuses on his own country rather than cheap expanding to increase the Development "Size" of his country, and this would allow Småland to finally be of some actual time to consider developing.
I am not disagreeing with OP on the topic of alliances, which should be able to be formed out of convinience, but it should be a lot harder (Have similar rivals, not border eachother and happen to come into conflict with eachother anytime soon, be able to perhaps have a dynasty between eachother) because I feel in every game that England allies Spain and basically GG France to dust unless France manages to ally Austria. Big countries have a lot of things they need to take into consideration before they decide to go to war, they can't just be some guy you found on the street but you have to pay them a large share for them to be interested. If England asks me Austria if I want to invade France with him and Spain, then I'd want atleast a third of the entire share of gold, which England might not feel like it's worth since England and Spain would probably do most of the work, and while it all comes down to that 100% warscore, there is just so many provinces you can take from a country in one war. France would die instantly and Austria would eventually have to deal with both spanish and english, along with the ottomans and polish.
What I am trying to say is that if we allow you to have like three majors, then the game will break because small nations will have no chance to effectively oppose them or anyone who didn't manage to find any allies (Aka France who is in the middle of three majors), but if we are going to work with 100% score is all you can take then the other majors would rather want to invade France on their own, where they can profit more. Forming alliances with Major MUST BE HARD, since they are all striving for World domination. Historically the Austrians were busy with the ottomans while the English and Spanish were busy in the new world. That is how we should try to keep it, so that France doesn't end up being pulverized.
Anyways, If England and Spain are to form an alliance against France, then it should be out of convience, like say France about to conquer large portions of spain and the HRE and becoming an unstoppable blob (Again Napoleon), but should only be there to "Check" France, not to ravage it like Poland.
On another Note, please fix trust, it's just too Hard to regain trust once it goes too low and you will never have a chance to ally that country again. Give also countries 10 or 20 favors at start so that they don't have to wait until one of them declares war or are attacked before you can use the alliance. IMHO favors AI too much who doesn't care about my feelings.
