The one thing I hope if there’s going to be official civ modding support in the future that it won’t work with specific data sets but more like how other strategy games like Civilization do it aka you can have different additional civs from different creators in the same game and don’t have to choose between them.
It would still be way better if at least some of them would come officially in the game, because modding all those graphics, especially new architecture sets and the destruction graphics will get extremely time consuming for the graphic modding community if they bother create them which isn’t guaranteed.
Also getting unique voice lines isn’t easy either. Some of them are already in other Age games which might ease the task though.