for sure.
The champ needs to feel smooth or fluid
I mean he feels pretty smooth for me but I find this quite subjective.
Be very versatile (build and lanes)
Can be played in any lane and any role (I wouldn't recommend top as he has pretty weak matchups up there) and he's actually more viable mid than jungle if your mechanics are really really good.
Have the ability to carry
http://prntscr.com/gsxb2o (plat 3 elo games)
Have depth
To be fair, you have to have a very high IQ to understand playing Master Yi. The mechanics are extremely subtle, and without a solid grasp of advanced knowledge most of the mechanics will go through a typical players head. There's also Master Yi's snowbally outlook, which is deftly woven into his characterization - his personal philosophy draws heavily from many types of penta kills for instance. The players understand this stuff; they have the intellectual capacity to truly appreciate the depths of the gameplay and lore, to realize that they're not just mechanics they say something deep about LIFE. As a consequence people who dislike Master Yi truly ARE idiots- of course they wouldn't appreciate, for instance, the humour in Master Yi's catchphrase "anger gives motivation without purpose" which itself is a cryptic reference to classic literature. I'm smirking right now just imagining one of those addlepated simpletons scratching their heads in confusion as Tyler Eltringham's genius unfolds itself on their computer screens. What fools... how I pity them. And yes by the way, I DO have a Master Yi body pillow . And no, you cannot see it. It's for the ladies' eyes only- And even they have to demonstrate that they're within 5 IQ points of my own (preferably lower) beforehand.
Not necessary but preferably no mana
He does have mana issues until you get jungle item, corruption potion is almost mandatory in solo lanes.