I’d like to add a few:
The Mississippian civ concept (with campaign ideas (The Cahokia and the Hernan de Soto ones) from the below thread:
And the initial Balkans civ idea from the below thread: Adding Romanians/Vlachs and Serbs, making the Dracula campaign (with some modifications) the Romanian campaign and then adding a Magyars campaign on top of it.
And an original idea of mine, a “Barbarian Invasion” themed DLC, with Vandals civ and one other Barbarian-era civ (my thought is Saxons but i’m open to other ideas on the second civ) A Barbarian architecture set for the new civs in the DLC, the Goths, and the Huns, and a campaign for each of the new civs and for the Romans (perhaps making the custom Aegedius campaign official, or another Western Roman commander fighting off the Barbarian invasions.)
After the Balkans and the Barbarians idea i’d personally prefer that Europe be considered “complete” and more focus be put into Asia, Africa, and the Americas. the below ideas are less fully fleshed out but I think have potential.
(I think that outside of the Mississippians idea theirs room for at least one other DLC in the Americas, with perhaps Chimor and Tariscans (pardon my bad spelling) though I haven’t done much research on this
I also think a SE Asia DLC with Siam and Champa
Assuming the next DLC is bringing Tanguts and Jurchens, I think another with Gokturks and Tibetans (or another civ if MS is still nervous about Tibetans) would be nice to fully flesh out both the greater China area and Central Asia (Tatars are later-era Central Asians, and Turks really is Ottoman-centric, a civ representing the more nomadic early turks would be nice)
This…is going to go back on my “Europe complete” thing but some form of Andalusia/Moors civ to represent the Muslim populations in Iberia I think has some potential as well, though that’s fairly far down the list IMO
A sub-saharan Africa DLC or maybe even two with any combo of Kongo, Benin/Dahomey, Swahilis, etc.
I’d also like to see full campaigns for all the pre-existing civs that don’t have them, and on top of my “Barbarian” architecture set i’d love to see a non-Japanese East Asian set, and the Byzantine set that has been floated around as an idea (and ideally Mississippians getting their own North American set if that civ ever came) but I know that getting new architecture sets seems to be anathema to the devs sadly so i’m not holding my breath for that.