Not really a side story, persay, but I'd like it if they upgraded the SMN egis from Titan, Garuda, and Ifrit to be Sephirot, Sophia, and Zurvan. More powerful primals with more powerful Egis!

As for actual side stories to continue, I'd like them to run one for another Naadam, or another big thing on Azim Steppe.

A side story where Rhoswen and Carvallain get hitched after some less than obsequious back and forth would be cool too.

It'd also be nice if the Sky Pirates from the Void Ark questline came back into play, and we got to go up to the Red Bill's Sky Pirate island. Be even more b*kupo*in' if they somehow bought the rights to the music from Skies of Arcadia and got us some remixes of the music from that game.

I'd also really love it if the city-states updated their travel airships. They're charming little things, but it seems like Cid's supplied nearly everybody related to the story with Excelsior models, so I'd love an update to that.

Also I'd really love it if in Endwalkers the Gold Saucer gets attacked, and then becomes a dungeon, and you have to beat the dungeon version of it before you can get back to getting your cactpot done :3c

Ok, I'm just spit balling ideas instead of side stories, better stop lol. *briefly imagines how cool it'd be to see Marcechamps ride in with a buncha Tailfeather Chocobo hunters on the backs of red chocobos to stop the Telophoroi* A man can dream though, a man can dream~