A couple things people seem to have forgotten:

With the recent slew of changes, there seem to be a few people are missing. Or misreading. Or misunderstanding. Or MS word. Something or other is failing to connect.

Namely, there's a nerf to Lee on the PBE, and the recent change to Thornmail. I'd like to hit "oh em geee ADCS/Death'sDance/Lifesteal so OP!!!111" in this, too.

Let's work in reverse order of change, shall we?

So. With Lee Sin. Who is he? A jungler, usually. His power is centered in Early Game, caps off in mid game, and wanes in late. He goes from a cannon to a pool noodle, as he's forced to build armor to even live in a teamfight. The current nerf on the PBE is removing about 3.5 of his base AD. This is coming shortly after a -5 MS nerf. Now, I know. Those are very small numbers. 3.5 AD per attack to a champion seems like literately nothing. 5 ms seems abysmal.

What you may not realize is that 3.5 AD is a lot when dealing with jungle monsters. 5 ms is a lot for someone who has to walk around. 5 ms is the difference between being able to kite that Darius or him keeping up with you.

3.5 AD will almost certainly add another attack required to kill some monsters. This may mean almost nothing, if it's just Gromp. You won't necessarily even take more damage. Just about a second of your time more.

But if it's small raptors? That's suddenly a lot more damage you're taking. That's another minimum of 5 attacks more in one of the camps with the highest execute rate. Second only to Baron Nashor, I believe. That slows down his clear of that camp by an easy 7 seconds. That puts him behind the enemy jungler by 7 precious seconds. And that's just one camp. And only the small ones from it. You can expect a delay of 15 or more seconds before he full clears with this nerf. And he may possibly lose a scuttle crab. Or both of them. He won't be able to invade as fast. His early ganks (which are vital), are slowed down. He will also take significantly more damage. Sure, not enough to force an early back, but it's reasonable to expect 50-150 extra HP taken. And that's not considering Raptors themselves just executing him.

There are more effects, but they're pretty small. Just keep in mind that he's losing a lot more than the numbers themselves indicate.

Next. Thornmail. It's seen as a pretty shitty item. Its passive has been, while certainly interesting, kinda useless in many people's opinions. Unless you're Rammus. In which case, it was far better than "Okay".

Sure. Its damage was cut by quite a bit. It was cut from reflected damage to flat (so theoretically better in early game, worse in late), and the armor scaling was reduced. By a lot. 25% down to 10%. That's a big nerf on a supposedly crap item.

Here's the thing.

It was never meant to be a damage item, except perhaps against minions (seriously. That shit did a lot to minions. Sunfire cape had nothing on it). It was meant to counteract lifesteal. It's not coincidence that it just so happens to reflect 15% of incoming damage, which just so happens to be the exact same amount of lifesteal on BorK, Elixir, Death's Dance, and Gunblade (technically three of those aren't _life_steal, per se, but that doesn't matter here). It's no coincidence that, in practice, it'll just so happen to reflect back the same amount of damage being healed by Bloodthirster (actually slightly more, because of armor being useful as things besides Thornmail's damage).

However. The problem?

It didn't keep up.

As more life steal items existed, it went from totally counteracting lifesteal (and then some), to it being theoretically possible to still heal off of it, to it being viable to heal off of someone with it on (BorK+Death's Dance is now no longer an a-meta, unusual thing. It's now just slightly unusual, but still done).

So a change was necessary. Flat scaling let it become useful in early game, and it was given Grievous Wounds. This means that no matter how much sustain they lumped on, it'd be useful. Even with a BT-BorK-DD-Elixer-SV-Gunblade Nasus at level 18 (an effective 75% Lifesteal, before SV's multiplication), it'd be useful, rather than being a minor irritant, and barely counteracting his passive.

And, as one person pointed out in a comment:

1.8% lifesteal [from Doran's Blade] isn't enough to cover 50 damage per auto unless you're dealing 2700 post-mitigation damage per auto to a heavily armored tank. A Vampiric Scepter won't help unless you're dealing 900. Death's Dance will only help if you're dealing 550 (Draven and Jhin might be able to cover that).

And, as we all know: Draven's actually kinda busted, and Jhin gets high AD because he's forced to have a shit AS.

That means you legitimately cannot heal enough off of someone with the new Thornmail to not die unless you have 20%+ Lifesteal. Which is only possible with Bloodthirster, a combination of runes, masteries, and BorK/DD/GB/Elixir, or a combination of items. Only Draven's busted ass can rush Bloodthirster (then again, he could rush just about anything and it'd be viable. Bias? What bias? It's not like I hate that narcissive, 1.2k Shiv crit piece of bullshit or anything) and still do anything. Most ADCs are forced into BorK>Zeal item>IE, or Zeal>IE>Zeal item>sustain. Before armor/mr is taken into consideration for buying. Usually, an ADC needs IE, Berserker's, a Zeal item, sustain, another Zeal item or Essence Reaver, and then they can finally buy their defensive item. The only thing you might be able to sacrifice is your second Zeal item. Even then, you leave yourself with very little to work with. You may be able to swap it out for BorK, but you also would get as much use out of a second defensive item (typically the other of Maw/GA, since you had to buy the other for your first defensive item). You could sacrifice boots, If you have a support to give you enough speed. Maybe.

So. As it sits? It's far better than you'd think. Power was shifted, yes. The passive took a big hit, and its armor was reduced in exchange for some HP. But it most definitely was pushed to its original purpose of counter-acting lifesteal, and it does so far more fairly, by not forcing an ADC to buy Bloodthirster or die trying to auto attack you. Just remember: It was NEVER made for the sole purpose of making ADCs unable to hurt tanks without dying. It was made for the purpose of tanks not being power banks.

So. Sustain items. I hit this a bit, before: An ADC cannot afford to buy nothing but sustain items. Usually, they can't even afford to buy two. They just don't have the space for it. Nobody does. And the ADC, being a very naturally squishy class (typically only enchanters are squishier naturally, and assassins are roughly tied), needs to buy a decent amount of MR and armor to actually survive a wave of burst. If he's lept on by an Elise and stunned, he's utterly fucked. Even with Death's Dance, you aren't healing fast enough to counteract that damage.

I'll take a moment and address one particular thing that continually annoys me: #Death's Dance is NOT damage reduction! It's a damage DELAY. It delays 30% of incoming damage, then deals it to you over 3 seconds. For comparison, Ahri's charm at max rank lasts 2 seconds, as does Morgana's Q at first rank, later reaching 3 seconds at rank 5. Ashe's ultimate's stun has a maximum of 3.5 seconds. It slows down an assassin from instakilling an ADC. It may stop a Zed from killing that ADC with his ultimate directly (therefore not gaining the AD). It does not stop an assassin from killing an ADC. They still do more than enough damage. It delays 30% of the damage. Take a theoretical champion with no armor, mr, and 1k health. If you wanted to instakill this champion normally, you would just have to do 1k damage. If this champion has DD, your 1k damage would only deal 700 up front, allowing the champion 3 seconds to heal enough to not die. Assuming you do exactly 1k damage, and ignoring health regeneration, that means this champion has to recover 1 HP. So literately any auto attack will save it.

However

Assassins do well over 100% of a champion's maximum health. Realistically, an Akali can expect to deal 130% of a champion's health before her ultimate runs out of charges (personal experience tells me this is roughly true), assuming she has Gunblade (more, with serious AP items. Let's assume Banshee's Veil and Zhonya's are her other two items for now, though), and the opponent hasn't yet bought MR (the fool). Assuming this is an ADC with IE, a Zeal item, boots, and DD, you can expect about 1.21 attacks per second, at...what, 200 AD? With a 50% chance to crit for 250% damage? About there. (I'm guessing a lot with these numbers, sorry if I'm wrong. Anyone willing to give me accurate numbers, I'd be happy with them!)

Anyways, so that's an effective 325 damage per hit (pre-midigation), assuming the ADC crits exactly half the time. With 15% of that healed every attack, that's 48.75 health per hit, and 59 health per second. If hitting something without armor. That's just under 180 hp over 3 seconds. We've covered that Akali's doing 130% of a champion's health pretty damned quickly. Assuming our illusory 1k health champion, that means 1300 damage was dealt (yes, unrealistic. An Akali can expect far more than that from her ultimate, but we're working with simple numbers here, so be quiet). 180 is less than 301, the amount the champion would have to heal to not die. This means the champion still dies. Even if he does, let's not forget one tiny detail:

Akali almost certainly has .

That deals another ton of damage (enough that, if you applied all of it at once, with Akali's damage, Death's dance wouldn't be enough to survive at all) and applies grievous wounds. Which, as we also covered last section, cuts healing. This means that this ADC is not surviving. Even with DD. Even with a Janna shield. It just won't be enough to not die. Period. That's how life works.

An ADC isn't surviving your burst because of Broken Items(TM). An ADC isn't surviving your burst because of Overpowered Shields(C). An ADC isn't surviving a burst because of Champs Gutted by Rito's Favoritism [Copyright applies to all nations except N. Korea, Canada, and Wyoming].

An ADC survived because you didn't pay attention, and were chain-CCd by 2 people (the other two being the ADC, the Yi JG, and the Tryndamere that's split-pushing non-stop) and bursted for over 3 times your health. Because you're squishier than Jello and didn't pay attention.

That's why. You were outplayed. Assassins aren't unviable (at least, not because of that reason). Sustain isn't busted. You're just bad. It's not Rito's favoritism [Copy machines have rights]. It's not ADCs being busted.

tl;dr: Sustain isn't busted. New Thornmail is good. Lee nerfs are far stronger than you'd think.

Sorry for the rant. Just annoyed at blatantly untrue information.