Something potentially interesting I’ve never seen explored is the possibility of Michiru and Setsuna having a friendship that’s a lot more child/older sister than true equals, not quite the same as how Chibs and Sets are, but similar. 

I mean, Setsuna is impossibly old, and while Michiru is mature and polished and has had her childhood taken away in a lot of ways, she still very young. I could see Setsuna, with her seemingly endless knowledge and the burdens she shares with the outers, becoming a safe haven for Michiru. There’s no pretense with the guardian of spacetime, she knows all (or seems too) so Michiru might as well be open. And Michiru is a teenager in all this, scared and hurt and young. Setsuna can’t help but see how young she is and ache for this child.