AD Carries need to have their late games nerfed
Because as it stands, with the exception of a few assassins and mages, ad carries are the only true "late game fantasy" roles. Everything else baring assassins is designed to support that basically, even if unintended. Their DPS is unmatched, their ability to buy items that give them great DPS and tank shredding at the same time is way over the top, they are bar none the best seiging class and they are the only class that is good at every single stage of the game.
The truth is, champions like Fizz and Zed are overpowered as fuck. Not only can they gib squishy targets and escape the grips of death when going in through both their kits and itemization, they also have the ability to innately destroy tanks with ease. But in a world where very few things challenge the power of the late game AD Carry, I can in no way promote the idea of nerfing the last few things left that have the capacity to threaten AD Carries.
So what's the problem? Well being ranged is a huge advantage - as it should be. However, not only are they ranged but summoner spells like heal and flash are more beneficial to them than other champions because of escapability shooting through the roof. Support peeling with both their kits and itemization is by far better than it has been and takes minimal efforts in a lot of cases, several of the ADCs are already mobile with CC. So in combination with their DPS, their survivability is through the roof despite being really squishy.
So what is the answer? Nerf everything they are taking advantage of? Nerf summoners, a class of champions and their itemization because of ranged ADCs? No, you shouldn't nerf those things. In my mind, what makes ADCs so absurd late game is the power of botrk + last whisper. Think about this, when you consider efficiency and just pure stats, a lot of tank itemization in both health and health + armor is amazing - until a late game carry gets botrk + last whisper. Once these two items are purchased, nothing is tanky anymore because not only are ADCs now able to cure through their defenses, this build path is common and still keeps their DPS high and they're still itemizating in both raw AD and crit on top of that.
I'm aware that a full DPS build should do exactly what it sounds like: kill shit. And kill shit fast. But a champion itemizing fully defensively and disappearing in a matter of seconds to an ADC is just plain bat shit crazy. Because what you will forget is how practical is it for a champion looking to be durable to itemize in just armor? He can't, a Mage will destroy him then. But is that really a mages fault? You didn't build MR - what did you expect. But think of the choices the tank has: try to stack armor and as much health to mitigate as much burst as possible from the AP or invest in one or maybe 2 mr items and have an ADC legit kill you in just 4-5 autos if that? MR is bad but in reality, to an extent, it needs to be. I could preach on wanting more variety in MR but that's a different story. Armor and health itemization has more variety and utility and strength than MR does but it's still not good enough. Not because it's weak, but because it's easily ignored once an ADC builds botrk and last whisper while BOTH items being purchased don't really harm their overall DPS.
And that's a problem. The only way champions are being tanky right now is if they have absurd damage reduction or insane defensive steroids (think Rammus and Leona W). That's it. If you don't have one or both of these, no matter how much defense you invest in, you won't be tanky late game. These defensive amps on champions are absurd in their own right but it's the only way to realistically be durable. If the ADC late game took a hit where tank shredding had to be an actual choice and not a convenient tag along, you could easily look into reducing these defensive steroids. After all, Riot has states they hate invisible power and damage reduction or massive resistance increases are exactly that. And in that same context, if the ADC late game becomes weaker, you can look at legit nerfs to Fizz and Zed because in reality, they have the same issues but their focus is largely on killing squishies, not tanks.
Overall, if late game carries were to see this nerf, true tank shredders suddenly look viable again once ezpz gib the squish assassins are toned down. Suddenly Kog, Vayne and even Varus look attractive again. Caitlyn becomes more of a lane bully and comes back to counter this. Ez and Graves fall into safer choice picks again and they find their place. Even Ashe, a utility carry, can have a place again because being weaker in damage is a death sentence for ADCs these days. In my mind, starting from the top (nerfing the power of late game carries) then going down is probably the best balancing pattern and likely the healthiest for the game.