I dont know what platforms you play on, but if you play on pc, alot of the features you want is actually here.
Diplomacy as a standalone is one of the if not the best mod for the game, as you can tweak the settings yourself with MCM, which can lead to very organic and random games.
There is huge overhauls that change the maps, some just change the kingdomes, split'em up into more factions, some into more clans added etc.
I know that atleast 1 mod have navalbattles as proof of concept(but last I checked not for vanilla, but for its specifc mod, no doubt down the line the code will be shared to be added as a standalone mod(or so I hope).
There is mods that add in more land, and use all the maps, like some of the big islands in the sea between the Empires and Aserai, is suddenly populated by relative powerful factions.
Again this is for pc. so if you are on console, ouch.
Do I want at the very least the diplomacy features be added to the vanilla game by TW - for sure, so that the console-ppl cant get a much better experience.
Playing vanilla Bannerlord is legit trash imo, really an awful experience, just to grindy, static, the same thing happends in each of my games, Battania gets ganked to pieces within 5 yrs, one of the Empires will then fall, typically Southern and Northern.
With the diplomacy mod, its much better for me now, and the games is really organic, Battania being able to survive(unless I do playeragency on them and destroy it, but otherwize they do fair) same for all the other factions, they can even make great comebacks even.