You need to be more specific. How do you envision any of these things? You can write what existing mechanics you would want to use for what you envisioned
If you have it well planned out I can help you with some things, but my modding skills are mainly for my own use, so it's harder to make something as impressive as AtE or AGOT for example
Okay so i was thinking with the sejm, it could be its own tab on the top left next to the societies tab.
When opening, it brings you to a screen that shows a list of all nobles in the sejm and who the marshal of the sejm who is at the top of the list and next to that it shows how much these nobles’ votes are worth (for example when playing as the Byzantine empire, depending on your status your vote can be worth more)
And you need to get 51% of the votes to get a law passed. Aswell as all of that, to actually decide what law to pass there will be a button that looks similar to when you want to reform a religion (this button will be located in the top left of this “Sejm tab”. Upon pressing the button it will bring up another thing that looks like the screen where you pick what attributes your reformed religion would have, the difference with that is there will only be one box not four and when clicking that box will show a variety of laws you can pass for example (Mass Conscription, War Taxes, Religious rights etc) i still need to think about what to choose.
When it comes to making the lithuanian and russian ai form the Grand Duchy Of Lithuania and The Russian Empire. I was thinking you could decide if you want the ai to actually do that in the settings right before you start a game. If you choose to let the ai form the two states it will make the game feel like your playing poland in the 1300s - 1600s. If you dont choose this option youll just have to deal with whatever the ai chooses to do in eastern europe.
When it comes to campaigning, you can spend money on your desired heir like how you would do when campaigning for your bishop to be cardinal. Next to that will be a button that shows you a list of all the people trying to get on the throne. This will be at the bottom of the Sejm tab. You can also ask different nations to back you in the election and there vote will be worth quite a bit so if you dont win then you can ask that ally you asked to support you to go to war to take the throne. BUT if you do ask a nation then after they might ask for something in return and if you dont do it then it can have dire consequences like war
When it comes to adding the Magnate title. I was thinking you could automatically earn the title if you hold 3 duchies and have 500 gold but the magnate title will only show up if the commonwealth has been formed and you hold these duchies titles in the commonwealth.
When it comes to adding these families:
Czartoryski, Kalinowski, Koniecpolski, Ostrogski, Ossolinski, Potocki, Tarnowski, Wisiniowiecki, Zalaski and Zamoyski.
I was thinking that upon forming the commonwealth. You will get pop ups saying that “The Ossolinksi Has Rose To Power through politics” for example. The pop ups will be the same to when your playing as a merchant republic and a family has died or has rose to power. All these families will pop up at once. Upon these families rising to power, you will notice these families show up in quite frequently in the Sejm. And these families might get some landed titles overtime
When it comes to adding Wawel cathedral, it could be that it shows up on the Krakow tile as a Level 2 building in the 1066 start and going forwards. The picture would probably just look similar to one you find on google lol. And the Cathedral will give you extra piety and prestige and will bring different intrigue options like the Hagia Sophia. Not only that but it could bring different diplomatic options aswell where your opinion could go up by 5 (or something like that) you will also be coronated there if your a king and
Adding the 1569 start date may be a bit overkill for now but it would basically resemble europe in 1569 with the commonwealth. When playing in this start date it will bring a few option like sponsoring a renaissance scientist or artist who can give you military, cultural tech etc. I was thinking maybe 100 tech points. There could also be options to explore the new world where you go form a polish colony but adding the whole world map maybe a bit tooo much.
Ultimately i was thinking the mod could make the game go up to 1795 or 1815. It would also be nice if the ai in general could form de jure states like the Austrian empire or the Ottoman empire or the spanish empire or the Swedish empire to just make it feel like your playing in that time period.
Im probably not going to think about event chains too much since this may be more than enough for now.
And to actually form the commonwealth you need to hold the de jure lands of Poland, Kievan Rus, Galicia, Moldavia and Crimea. And you cant have an heir yet and you need to have 2000 prestige and 1500 gold. You can either just invade these lands OR
If you turn to make it so the ai forms Lithuania and russia. You can let the Lithuanians grab the territory they need or at-least some of it and then right click on the rulers picture there will be an option to Personal Union (the other kingdom has to not have a ruler on the throne or they really like you) If they consent youll be able to raise Lithuanian Levies and interact with there tiles on the map but on the map it will still show Lithuania until you form the commonwealth. The Personal Union will look similar on the map to how you do it in EU4.
When your in a personal union, The crest with the flag of poland will have the Lithuanian crest right next to it. But then when you have formed the commonwealth the flag will change to that of the commonwealth. And the crown on top wont become an emperor crown it will stay as a king crown.
And once forming a pop up will show saying
The Formation Of The Commonwealth
And then it will talk about youve done to form it. It will be like those pop ups that talk about what going on in china
ALSO, the sejm tab wont show up until you have formed the commonwealth!
Thats all my ideas FOR NOW. I wont think too much about event chains and traits and whatnot for now and if you want me to elaborate on anything then let me know!