Updating Old Champions with New Mechanics?
Now, I'm not saying change kits or anything too fancy. Not like a full rework or even the class updates. I'm just saying maybe try stapling on new mechanics to old champions.
Like Lanna
could, instead of just give ad, give adaptive damage with her shield.
Taliyah
could, instead of gaining movement speed by "wall riding," actually ride on walls.
Riven
could, instead of a normal shield, have a physical damage shield.
Etc. etc. etc.