This is my suggestion. This suggestion will be very similar to other posts in this forum. I probably could post in an already existing thread but I’d rather make a new one for visibility.
Move the 3K campaign to a Chronicles style menu. That’s where it belongs. It’s an experimental style campaign with Chronicles style storytelling, even if it’s not “Chronicles by CaptureAge”.
Remove the 3K civs from ranked multiplayer. Re-release the bones of the civs as medieval civs. The ones that I’m the most interested in seeing are the Bai (which I think the Shu? can easily be turned into) and the Tanguts. I was disappointed that the Tanguts were heavily teased, and then they were combined with the Khitans, it would be nice to know if this was due to political reasons. If it’s not I would really like to see Tanguts in the game. I think another poster already posted a good suggestion about how to handle this - with the current Khitans becoming Tanguts and the Wei becoming Khitans and taking some of their features.
None of the ranked civs should have heroes. Heroes are campaign and custom map only units in AoE2.
The non-Medieval Three Kingdoms DLC ‘civs’ also had too many regional and unique units and new mechanics - again more something that suits a separate game mode rather than in the main game. These should be kept to a tasteful amount rather than for every civ. For example in Dynasties of India - two civs had multiple unique units - Gurjaras and Dravidians. The Shrivamsha Rider shield is one of the stupidest designs in this game as well, along with stuff like Flemish Revolution. This DLC brought too many of those types of mechanics all at once. Some of those should stay in the 3K chronicles.
I only play ranked multiplayer, with the occasional lobby game with friends but I do care a lot that things ‘fit’ in the game design. I really dislike seeing stuff that doesn’t belong in the game (Wu, Shu, Wei) in ranked multiplayer.
I’ve never had a problem with any of the previous civs (although I do think the design of some of them has been left by the wayside - such as with the Sicilians) - but this DLC is unacceptable to me.