Ancient china's warring states period would be epic, but onto other things.
I really want to do the TES series, but mostly because I'm angry/disapointed in how oblivion/skyrim let the lore from the previous games down. Skyrim was supposed to be a badass land with flying whales, werebears, badass ice vampires who live under frozen lakes, and most prominently missing; a fleshed out nordic pantheon, whilst Cyrodil, pre-oblivion, was supposed to be a tropical jungle filled to the brink with dangerous creatures. Infact, The first game was called ARENA because the continent was so damn dangerous and bloodthirsty, so I wanna make something along the lines of Tamriel: The Arena.
Set in an alt timeling (so far; Either the Daedra and Aedra came to an agreement to rearange the world or the dragonfires went out, septim did his thing, the world experienced a moment of chaos, the jungle that Talos removed came back, and the empire was too weak for it's hold. The setting awaits for someone to reunite the chaotic and fragmented people)
But I think this is a really difficult thing to do, because, y'know, there's so many perspectives on TES. Some people love skyrim the most and'll wanna put in everything I dislike about it, some'll want more fantasy armour, some'll want less. Personally, I want to do a "everything should be realistic unless it's magic" kind of approach, but arguably everything in TES is magic because the stuff flows from holes in the sky and permeates everything. Some people like the more conventional look for orcish and dwarven items, whilst I like old oddball look for dwemer stuff and the refined -we're actually the best smiths- look for orsimer. It'll be a real hastle, and I don't wanna be going "this armour you've painstakingly modeled doesn't fit" because I'll be a damn perfectionist but I've no modeling experience.
I want an artistic style that works well with bannerlord's existing assets, because I'll use a lot of those.
Also, I'm really dependent on how bannerlord'll do things to allow mods. Will flying characters be workable? How can I work in spells? Can I change attributes? Do you think I can put in some daggerfall style advantages/disadvantages? Can the fighters guild work? Can I create linear dungeon like levels, use a stealth section, or give the player the signature TES ability to loot everything? Can I get moon cycles to work?
How big can the worldmap be, because there's an average of 8 cities per country, and while I don't need to go for the scale of daggerfall, warband really chugs with big maps, so I don't know how viable such a large mod'll be.