I've mentioned a few times how I fee diplomacy and alliances are lacking and could do with more depth, I realize that's not an easy thing to address.
However I do have a smaller diplomacy QOL request that I think might be easier to address.
I think we badly need a "diplomatic relations" screen that shows all the following information in once location
-Each civ's relationship with each other (allies, declared friends, at war, trading).
-Your active treaties with each race including how many turns before they expire.
I realize that some (not all) of this info is available when you click on the individual civs but its very cumbersome and hard to get an overview of all inter race relations. There was a screen like this in GC3 so I dont think it would be hard to implement (apologies if I'm wrong on that).