It feels like league champion pool lacks age diversity. It would be really awesome to have this AD bruiser grandma beating the shit out of Darius with a walking stick at 2.5 attack speed. Well, jk, about the AD part.
But really it would be really cool if had this grand master of dome type of magic.. and she would be an elderly woman. It would add some depth to the game as in.. league lore does mention from time to time that there was some elder X, who taught the champion we have now the basics of something. So maybe RIOT could release a champion that would be just like that.. except he/she didn't have an apprentice.
It all comes down to that while champions do feel unique gameplay wise, it would be great if they would be more unique design wise - having champions all young and all kind of ruins the atmosphere. This is a game in a world of magic with powerful wizards and weird creatures, and yet we have no elder magic user, that pretty much most media related to magic use to create an immmersion.
Don't forget to upvote if you like the idea :) More exposure is never a bad thingy.