Riot, it's time for Lee Sin to be nerfed. No more love taps.
Ever since his release, Lee Sin has been THE dominant champion in League of Legends. His sheer mobility and early game power eclipsed many other champions. Over the 3 seasons he's been playable in, he's come in and out of favor, but he's always been one of the strongest picks in the game even when he was unpopular.
Before we talk about nerfing Lee Sin, let's talk about the specific reasons Lee needs to be nerfed.
CONTEXT WARNING: The portion of this post is for those players who do not currently believe Lee needs to be nerfed. If you already agree on this point, skip to the Changes section.
Mobility
Lee Sin is one of the most mobile champions in the League, even without his dual dashes. His base movement speed is a quick 350, slower then only Master Yi, Pantheon, Janna (thanks to her passive), and transformed Nidalee and Elise. This mobility makes him extremely strong at both traversing the map quickly and at ganking champions from the jungle or mid lane.
Strong in All Phases
Lee Sin's early game power is infamous, having been the originator of level 2 cheese ganks (yes, even before jungle Alistar in late S2!) thanks to the incredible damage on his Q and W. Against the average level 1 champion with 496 HP(derived using a spreadsheet I can't attach on the forums due to format issues), Lee Sin's Sonic Wave/Resonating Strike combo deals 104 damage before mitigation and leaves him in melee attack range with his 40% attack speed steroid up. While the most powerful level 1 skill, Maokai's Saplings, technically deal more damage and are also split into two parts, there's no way for Maokai to follow up on its use.
In the middle game, Lee Sin reaches his peak strength. A maxed out Sonic Wave/Resonating Strike deals a whopping 340 damage before ratios (180% bonus AD and 8% enemy missing HP) and mitigation are taken into account. At level 11, this means that Q->R->Q combo with no autoattacks included is dealing 800 (+3.8 bonus AD) out of the average level 11 champion's 1346 HP before mitigation.
Late game, Lee Sin is still extremely powerful against squishy champions, even if not heavily specced into AD. He packs above average bulk late game thanks to his good HP scaling and scaling MR, and is ranked as the 35th bulkiest champion in the game at level 18 using the Effective HP metric.
Versatile
Lee Sin's most underrated aspect is his versatility. He can be viably played as an assassin thanks to his over the top AD ratios or a bruiser/tank due to his extremely high base values. His meta placement is very flexible, and he works in either solo lane or the jungle with either of his two major builds. In combat, he isn't locked into any specific arrangement of skills or skill combo-instead, he uses skills whenever he feels like it and doesn't really suffer many consequences for doing so because of his energy use and short cooldowns.
But most of all, Lee Sin is essentially the perfect champion for jungling in League of Legends, as shown by his high pick rates and success rate in the S2 Shyvana/Mundo/Skarner counterjungling meta AND the late S2 J4/Alistar/Lee level 2 gank meta, which was arguably the biggest shift the metagame has ever experienced in a single season (other one would be the dominance of the European ADC/Support meta at S1 worlds). In fact, one of the best ways to measure junglers is to ask "am I handicapping my team by picking this champion instead of Lee Sin?". A lot of times, you are, and the only saving grace is that Lee hasn't been picked by the enemy team yet.
Overall, Lee Sin has been a dominant force in League of Legends for three consecutive season. He is viable in just about any meta due to his extreme early and mid game damage and his sheer versatility. And** it has nothing to do with Lee's kit**, which isn't inherently overpowered and in fact is remarkably clear and simple in what it hopes to accomplish.
No, Lee Sin's numbers are simply overpowered. Lee Sin simply deals too much damage with his Q and ult and scales far too hard into late game to allow his current ridiculous early game strength. Something on his kit has to give way.
Changes
Here, then, are some proposals for rebalancing of Lee Sin's numbers. Each one is tailored to gut one specific aspect of Lee Sin's current strength while preserving everything else. Please note that each option on this list is meant to be considered individually-if you applied every item on the list at once there would be absolutely nothing left of Lee Sin.
Early/mid game power: Heavily nerf Sonic Wave/Resonating Strike's base damage. Split Dragon's Rage's damage so that 40% is dealt upon kicking the enemy and 60% is dealt upon knocking up another enemy champion midflight. Remove the attack speed slow on Tempest (it effectively prevents retaliation in lane trades for many top laners. Increase the attack speed given by Flurry.
Late Game scaling: Switch the ratio on Sonic Wave to Ability Power, and force it to deal magic damage. Reduce the bonus AD ratio on Dragon's Rage to 1.0 or less.
Jungling: Change Lee Sin's passive to only proc after activating the second half of an ability; for example, Sonic Wave would not trigger Flurry, only Resonant Strike would. Remove the ability to use Safeguard on wards.
Versatility: Reduce Lee Sin's scaling armor and remove his scaling MR, forcing him into a tankier build. Remove the ability to use Safeguard on wards. Force Tempest to deal reduced damage against lane minions, making it easy to wave clear faster then him and pin him under his tower.
Any one of the above would be a good way to reduce his power to a reasonable level pending further balance adjustments.
