Champion designs are often scrapped, but they might still be useful for something.
Add them to the lore.
How cool would it be if Ceecee (Braum's original concept) was Grave's Piltovian gunsmith?
Or what if Taliyah had to fight Deadeye (Jhin's original... man some champions were completely different when they started off.) once she arrived at Shurima?
Having champions meet each other all the time makes the world feel small. So adding a couple new characters in the mix should spice things up bit.
What scrapped champions do you think would make Valoran a more interesting place?