hot take: the ADC update is less a direct nerf to ADCs and more a buff to Assassins.
Old LW back? That's massive, every AD assassin player has been begging for it back. Lots of AD assassins weave in autos into their assassination pattern. Enter Stormrazor and Hall of Blades. That 400 AD Zed is now going to crit on his first auto while not having to buy crit, AND gets more sticking power with the MS. Even if you Janna shield the Rengar jumping into your face, he can still catch up to you and kill you again. Also BORK is getting buffed as well. Lower upfront burst from scaled up ADCs due to the IE change (and they now take longer to get there) means that the fed assassin can run in and kill the ADC unless the support is Janna or Lulu, or he gets a point and click stun.
Obviously we need to wait until games are actually played with it (wish I had a PBE account) but assassins may well be returning to S3/S4 levels of power with these changes.
Also support nerfs may be coming soon.
I'm pretty excited for this even as an ADC player, yeah crit is strong and shit but it's boring and stale as hell, sometimes being OP doesn't translate into fun. Also I tend to play AD caster ADCs anyway



And put it on say....
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. A big balancing factor with his builds was that you had to decide between going pen, crit, or a mix. Crit build is best late game and vs tanks, lethality build spikes mid game and shred squishies, and 50/50 is in between. The thing with lethality is that you could build 1 crit item and if you got a crit it would no joke completely one shot an ADC 100/0. Now with the guaranteed crit you can build that and proceed to stack lethality/LW and crush.