What if you balanced the "flashy" champions too?
Wouldn't that be good?
I mean yes Thresh can make some of the most insane plays ever, but that is largely due to his kit being OP and Riot leaving it that way. The same can easily be said for Lee Sin, Fizz, and Zed. Thresh has too much lockdown to also have as much utility as he has. One of these should be nerfed, but then we'll see less awesome Thresh videos I guess, so that's a no go.
For Fizz/Zed, there's a different issue. I don't think Riot is comparing damage to mobility properly. When a champion only needs to go up one kill to be able to safely tower dive and kill you at 80% health, you can't even lane against them anymore, and the lane is over as soon as you die once(or go down x amount of minions, or just be the wrong champ). Since they're Fizz/Zed, you likely have to be defensive from the start since they are both nuts to try and trade with, which gives them higher odds of going up on you, which instantly loses the lane. How is it ok for a Zed to get a free kill every time his ult is up? Are you expecting us to just end the laning phase at level 6? How is it ok for Fizz to be able to dash 2-4 times per fight and still do enough damage to 3(or 2) shot any squishy he wants?
Lee Sin is just Lee Sin. Always has been and seemingly always will be the god of the jungle, and there is no way Riot can honestly think his skillset is balanced. I say keep the mobility and nerf all his damage(especially the Q). The Q is one of the longest range dashes in the game, it does not also need to be a huge damage hit. You make Lee do sub-par damage because he is the most mobile guy in the game, and then all the sudden those Lee plays actually mean something(Teamwork?). Right now the Lee plays are generally him going solo and doing crazy crap that nobody should ever do, and surviving because his W came back in time or because his kit makes it so the entire team can be chasing him and come up empty more often than not. That's not promoting teamwork at all, you're actually penalizing the team for trying to collapse on a huge threat by allowing him to almost always escape and waste everyone's time.