first step to fixing tanks: address their % damage
early morning post so it's kind of stream-of-consciousness. Note that for context, a lot of champs started getting % damage around season 3-4 to stop raw health stack builds from being a thing.
If you balance the game around the idea that if you play well, you can kill anyone, the game's best picks will immediately shift to the safest group that can kill anyone. We've observed this consistently; start of this season, season 5, (sort of) the Ardent meta (granted, you just picked tanks because of bot lane). What adding % damage to tanks has done is shifted them from a group who can threaten squishies with damage, and threaten tanks+bruisers with lockdown, into a group that can threaten anyone with their damage, and now deals the damage that directly counters fighters. Given that most fighter's core damage items are almost straight HP, the flat damage dealt to them from certain tanks actually increases as they build these. When tanks are the dominant choice, or if they just happen to get fed, the fighter cannot continue to build their core items because they're flat HP; they must put it off for resistances, which delays their power spike and shortens the time frame they have to be relevant before enemy DPS comes online and outscales them.
A tank's duty is strategical over mechanical; they exist to soak damage and provide crowd control. When a tank is now providing hefty chunks of damage in fights - more specifically, %Max damage, which is fairly target agnostic since it deals the 'same' damage relatively, to everyone - you now have a third thing occupying a tank's power budget. While, maybe not directly, my thoughts are that this has had a long-term effect in powering down their ability to soak damage; because if even tanks are putting out % damage, then everyone is worse at soaking as a baseline, but because tanks are now doing relatively higher damage to fighters than they would have been in the old days, fighters have had to be buffed to put out more damage in kind. Notably, since tanks are what have given them the biggest existential crises, we've seen a rise in mechanics on fighters that bypasses a tank's main strengths completely - true damage, since tanks rarely buy raw health but almost always invest heavily into resists, and armor reduction. Black Cleaver used to be flat armor shred (granted, we had Battering Blows and lots of fighters used to buy Last Whisper in the old days), juggernauts like Garen and Nasus have had % armor reduction added to their kits, etc. Conqueror doesn't need to be said, we all know about it. This new availability of these items allows fighters to skip out on buying much more besides maybe a Cleaver, so instead they can buy lots of raw damage items like Trinity and Titanic. What happens then is while they're innately well-equipped to fight tanks now, they essentially turn into durable assassins against anyone else.
The effect of this has been a somewhat 'normal' shift back into the classic paradigm where a fighter would beat a tank in a duel, but it's now much more volatile than it used to be. This can be partially attributed to the current snowball heavy meta, but where a tank's original 'win condition' was to stonewall the lane and try their best to farm, which was undeservedly decried for lack of interaction, they're now incentivized to be actively trading and fighting to get ahead, which puts them at odds with the fact that there's a good chunk of fighters designed specifically to destroy tanks in these exact circumstances. Ironically, now that tanks have all but disappeared, and this plethora of penetration and armor-ignoring features is so prevalent, we've come full circle, and stacking straight health ends up being better than getting so many resistances.
My opinion: the addition of % damage is the root cause of the circular balancing and has led to an aggressive power creep amongst fighters. Hammering out each of these issues would, IMO make for a stronger long term solution than the constant band-aids to punching tanks like new IE and Conqueror. I don't expect this to be a popular thread just because tanks aren't amazing right now, but when the game shifts to bring them back I wholly expect it to be a repeat of what we've observed a few times; tanks do enough damage and have enough CC they can threaten anyone on their own and guarantee death with their team behind them, so tanks will just become the best thing to pick either in top, jungle, or both. People bitch, Riot buffs fighters and nerfs tanks just like the start of this season, and then a few months later it switches again. Let's break the cycle here.
because of W>Q>E>Aftershock>Enhanced AA -_-