I can't picture them as a ship pairing, however I can see Discord and Fluttershy being very close friends after the episode those two had. If he does show up in more episodes I can see Fluttershy playing the "Voice of reason" for Discord. Also known as the angel on his shoulder.
Yeah, they have a pretty dynamic friendship going on here. If Discord shows up in more episodes this season I think Fluttershy would be Discord's "Shoulder angel" considering that he is still Discord even if he is willing to be nicer. He would still be the mischievous prankster... Actually seeing Discord episodes with him trying to be helpful or solve a slice of life problem would be really interesting with a character like him.
I'm thinking Discord could give himself the appearance of age while she's still alive. What might be sadder would be when she dies...and he's all alone afterward and never able to see her again (one of the many downsides of immortality).
Don't count on the princess other then messing with the sun and moon there not good for anything , she did what they couldn't and got discord to chill out by being nice to him and calling him her friend she was kind but firm.With all there power they couldn't do jack he could kill them all with the snap of his fingers but being nice to him fixed it how hard was that?