ADCs as a class weakness should be that they are extremely fragile. They should never be able to 1v1
pretty much anyone. They should have high consistent damage that is designed to kill tanks but NOT be able to BURST squishies. Even other ADCs.
Essentially, ADCs should auto-lose to tanks, fighters, assassins, and mages if they have no peel (such as a 1v1) as that should be the defining weakness of their class. Obviously champions like Vayne will be better at 1v1ing due to less range, but by default if they are an auto-attack centered champion they should not be able to reliably 1v1 anyone on their team. They should be so fucking squishy that anyone looking at them sideways should be able to murder them with burst. ADCs should never be allowed to out-burst mages or assassins under any circumstances. They should rely on good, safe positioning and peeling teammates in order to do their job. They should not have warlords granting them massive lifesteal pre-mitigation, they should not have several forms of accessible % damage reduction without losing damage at all and should NOT spike at two fucking items.
Beyond this, they need some strengths as a class. They should have the highest consistent damage (DPS) that does NOT result in burst per second (BPS) that we have now - ADCs criting squishies feels like insane burst damage. This is extremely difficult to balance because a great deal of ADCs have late-game orientated weaknesses (supposed to be weak early) but due to circumstances beyond those specific champions, their weaknesses are irrelevant, so they are strong all game. Good example here being Tristana, Twitch, and to a lesser extent, Kog'maw.
This is a grand ideal, sure. How do we accomplish this? Well, I personally think that crit items should be geared towards dealing with tanks. This means that crit damage as itself should be LESS effective against squishy targets, but more effective against armored targets. A possible solution would be to make crit damage scale from 150% to 250% depending on the targets armor (but somehow not tied to stacking ad.) This is like giving ADCs % health damage (this is a very common tool used by Riot to make sure certain champions will always be able to do a certain % of damage to tanks without completely murdering squishies) except it has one strength that normal % health damage doesn't - it cannot promote a tank playstyle.
This means that tanks can do what they need to do - tank damage from the enemy team, but the class that's supposed to beat them, the ADCs, can, while the class that's supposed to shit on exposed ADCs, assassins, and to a lesser extent mages, can also do so. ADC items also need to be toned down in the amount of damage reduction granted to ADCs. This also opens up room for ADCs to specialize in deciding who to focus.
Enchanters are bound to be nerfed (as the amount of flat hp they grant ADCs just make their % reduction doubly effective) so we may not need to completely cripple those items. However, we need to make ADCs have more offensive and defensive centric items. Shit like GA should be catered towards bruisers, not ADCs. Shit like PD should grant more movement speed and attack speed but limited damage reduction, if any at all.
Lifesteal on ADCs should need to be specced into. Give ADs the ability to purchase bloodthirster and attack speed to better be able to kill squishies if they want, or spec more into crit to be able to more effectively deal with tanks. Right now ADCs as a class being so strong (due to multiple reasons, shit like enchanters, strong tanks, retarded itemization, etc) means that it's horrible for everyone.
ADCs, ask yourselves. Do you like having 3-4 people bot before 15 minutes a lot of the time? Do you enjoy ALWAYS having a jungler ganking your lane every fucking minute? Do you like being destroyed by that ADC who managed to get a BF sword before you, then get IE, and then be fucking impossible to deal with to the point that it's hard to farm under turret? No one enjoys that shit. Mid laners don't enjoy ADCs fucking up their mid lane at 15 minutes. Top laners don't enjoy ADCs showing up top with 2-3 kills while being impossible to shut down due to the peel and disengage shit like Tristana/Janna has. ADCs being this strong creates such an unhealthy relationship that it warps the entire game. ADCs being huge early means that towers, dragons, barons, everything gets taken quickly. Games end in 25-30 minutes because one side stomps so hard that games are boring. You know whose going to win within the first 5-10 minutes 90% of the time.
It sucks, and it's extremely frustrating that Riot cares so goddamn much about their precious esports that they let this shit fly for several patches instead of fucking addressing it and tuning as they went so it creates an INTERESTING experience in esports.
needs reverting.
should not exist and needs removing. Lifesteal should not trigger on bonus damage, or crit damage. Those would be the first changes I'd make for Season 8, I'd leave damage alone and see how it goes.