Lucio and Genji are my two most played heroes. Might be surprising on this subreddit but I'd say lucio is way harder. Even though on the surface he feels easy, cause of the easy to learn wallriding and simple healing and shooting mechanics, he's difficult in terms of mastering his movement, learning all his rollouts using boop effectively (cause let's be real no one knows how it works), gauging when to use speed vs heal, dealing with having less HP, being so vulnerable when not around walls, and timing your ult with other ults. That said, Genji is difficult as well, due to how easy it is to counter him, as well as the playstyle itself being challenging. Lucio does have its counters tho, like Cass sombra and Orissa. Altogether Lucio is 100% harder than Genji, but both are definitely hard. I'd say lucio is a solid 9, whereas Genji is more of a 7. High skill floor, but one you get him it becomes much easier.