Kayle and Morgana's lore + in game champion interactions
Patiently waiting for Kayle and Morgana's outdated lore to be retconned so their origin is in Targon. Not to say they are aspects, but that they came originally from Targon, such as an elite Targon class or something. Their own dispute could partially explain why Targon's influence wanes due to the residents disputes. Like either their dispute was the catalyst, or they are just one of the more recent Targonians to have a falling out as Targon's citizens take sides in their large scale agreements. Just seems to make sense.
Also waiting for Kayle and Morgana to get a mini game like Kha'Zix/Rengar and Ashe/Sejani/Lisandra. Also every other set of champs that has an explicit Lore dispute should get an in game mini game/interaction Leona/Diana Aurelion Sol/Aspects Shen/Zed or Shen + Zed/Jhin Others (what else is there?)

will have their own bird-person race and kingdom, because of their winged appearance, it is basically suggesting their entire civilization share the same trait, though it could just as equally be written to be a trait unique to the sisters.
100% going to be from a floating kingdom if not Targon.
vs
quest needs to become a thing! RIOT PLZ! As well all the other minigames you listed.