Some champions are CC priority champions. Yi is one of them. Checking out your op.gg, you're not even level 30 yet. I'll guess that you've been playing this game for 4 months, tops, since that's how long it took me to get to level 30 back in season 1 before they gave you 10 free EXP boosts while you were leveling up and halved the amount of EXP it takes to level up. Yes, CC counters every champion in the game, but there are some, like Yi and Illaoi, that you always CC first. There's a difference between throwing CC in to throw CC in and throwing CC at a specific target. As an example, I see you play a lot of Twisted Fate, get a gold card ready, wait until Yi Q's in, and then throw it at him. Your team dog piles on him in the 2 second stun duration and he dies. Or, if it's lane phase, you run away during the stun duration and he wasted his time trying to gank you. That's why these champions are completely nonexistent above gold. People figure that out after getting stomped by them up through bronze/silver. I remember back when his Q had a 100% AP ratio and his W had a 300% AP ratio, so he built full AP and was an unkillable monster. Or back in beta, when his ultimate was his current Q, but hit 10 targets with a 300% AD ratio, and his current ult was his q, exactly as it is right now but on a much shorter cd and without the passive reset. Oh, and the E that you complain about? The one that supposedly gives him 400 true damage at level 1? Yeah, that was a toggle that made his autos cost mana. It was basically infinite, though. Off your autos didn't cost mana, but he gained bonus AD. On, his autos did cost mana and dealt bonus true damage. You never turned this off. You wanna see broken? You shoulda been around in alpha/beta/season 1. Nothing was balanced, everything was everywhere, game was pure and fun. But if you compare that balance state to that of today, today's is significantly better.
Regarding the Yi buffs, taking a look at patch notes, it shows nothing, meaning that they're still on PBE and haven't gone through to live yet. For all we know, they won't. I do think that Master Yi needs a full VGU (Visual and Gameplay Update), not because he's broken, but because he's extremely overpowered in silver and below, while simultaneously completely worthless anywhere gold or above, which creates this dissonance where the bottom-tier players complain about him endlessly, but the game is balanced to the higher tiers when they can get away with it. A champion like Master Yi can't be balanced to be good in higher rating without completely breaking him in lower rating right now, which is likely what Riot are trying to do with the buffs. Make him at least viable in mid-tier and above ratings, while keeping them small enough that he doesn't become too strong in lower rating. I don't think that that plan is going to work and those buffs are likely not gonna end up making it through to live, though.
Also, 400 True Damage at level 1 is not true. His E gives, at RANK 1, 18 bonus true damage on-hit while active. Plus, he probably started Q at LEVEL 1 and then picked up W at LEVEL 2 since that's what most Master Yi players do, according to Champion.gg, so he won't even have this ability leveled at all until he is LEVEL 3. And regardless, if one of you survives long enough for his E to deal 400 true damage to you with 1 point in it and no bonus AD apart from runes (so maybe 20 true damage per hit, 40 when he Double Strikes you), you must be EXTREMELY tanky at level 1 while dealing literally 0 damage. Like, tanky to the point where Yi's autos do about 20 damage on every hit from his regular AD because most tank champions start the game with around 600 health.
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