I’m annoyed by always having to scroll down when leveling a hero.
Every locked hero is darkened out, so you can’t pick them. But they still show up in the list. There’s already the idea to filter them, so they don’t show up, which doesn’t get the attention it deserves.
I think an auto feed button would be even easier for the players. It could automatically pick all 1* and 2* heroes from the same colour, to feed them to your selected hero.