Pack it up boys, Skarner is dead.
Level 1 Q - exactly the same
Level 2 Q - 0.01 AD
Level 3 Q - 0.02 AD
Level 4 Q - 0.03 AD
Level 5 Q - 0.04 AD
This change is completely irrelevant before level 4, which is the only time Lee Sin is ever going to willingly fight Skarner 1v1.
Between level 4 and 9, it's 2-6 less damage per Q. That's a pathetic nerf. It barely impacts his clears, thanks to his spires giving him massive attack speed and mana regen, and it's almost irrelevant in ganks since you're dragging your target into your team.
It's only a serious damage reduction if you're building Skarner offensively, like Warrior > Black Cleaver, in which case you're doing about 15-20 less damage per Q after level 9. Given that all the good Skarner players are going Cinderhulk > Trinity Force > tank, it's a significantly smaller nerf than that - closer to 8-12 damage.
There's not much point in getting mad about Skarner getting nerfed and blaming Lee Sin, given that Skarner's winrate is 5% higher, it's above his average against Lee Sin, and this is in a meta which favours Lee Sin (early-game oriented, snowbally, good for AD fighters but not assassins).