I'm loving the game already. I'm likely gonna buy it the next time steam gives a discount.
It might be a stretch considering the game is still developing the fundamentals, but I think it would be very cool if you added a multiplayer option in a later update. I'd love to play this with 1 or 2 friends and I think it wouldn't impact performance a lot.
Other things I would recommend is an option to reactivate tutorials or see a wiki, because sometimes I forget mechanics after a couple of minutes. And an option to skip dialogs, because I read fast (or the explanation is redundant) and often I find it tedious to wait for the advisor to write the full paragraph of the tutorial to keep playing.
Other than that I'm not sure I can criticize anything else, because I never went all that far in the game and perhaps other ideas I have are already implemented. But I think it would be great if you added and official modding support. I can think about some nice ideas like personalizing the costume of the queen, his subjects and their guards. Or simply talking nonsense with our favorite subject while everyone else works. But you shouldn't work on mechanics so simple (yet, time consuming) when there's surely gonna be a modding community more than happy of doing it for you.