Talking about crit based ADC's;
They scale with gold. The more gold they have the more items they can buy and more powerful they become.
Riot increased the gold of their itens with the latest adc item changes.
Considering a balanced game
Before they finish 2 itens;
1vs1 situations ignoring tower presence;
You win.
Lane fase 2 vs 2.
They don't have dueling capabilities. They get bullied in lane. They need to farm.
Anyone can capitalize by ganking on them and score a kill if they made a mistake/ dont play it SUPER safe.
They RELY on the support to be able to farm and survive. If they cant farm they will fall behind.
After they finish 2 itens (
+
);
1vs1 situations:
The range that ADC's have at their disposal can be nullified easily in the absence of the peel a suport or team provides.
There are many melee champions with movement abilities that can nullify that range.
Mages can poke and 100-0 them with burst.
Assassins can close the gap and 100-0 burst them.
Tanks can kill them if they play their cards right.
1vs2 situations:
You are going to engage the adc and the support alone...
If you have a gap closer and burst damage: You can 100-0 the adc and proceed to kill the support and score a double kill.
If you have a gap closer and dont have burst damage: You will test your abilities to outplay 2 ppl, you can win if u play your cards right.
If you dont have gap closer and dont have burst damage: You will feed 1 kill for the adc.
After they finish more than 2 itens;
1 vs 1 situations:
If you can 100-0: You win.
If you cant 100-0 but you are a damage dealer: You will need to play your cards right.
If you cant 100-0 and you are not a damage dealer: You will feed 1 kill for the adc.
Team fights assuming the only problematic carry is the ADC:
If the adc team and/or support can peel and your team focus him: He dies, you win team fight.
If the adc team and/or support can peel and your team don't focus him: You will all die, you lose team fight.
If the adc team and/or support can peel and your team focus him and FAIL to kill him: You all die, you lose team fight.
If the adc team and/or support can peel and your team focus him and SUCCEED to kill him: He dies, you win team fight.
-Range can only be a litle more problematic in the presence of machanics like Kiting and/or Orb Walk, not all Adc's use this tecniques and you cant balance a role only thinking on them.
-ADCs are not self-sufficient they can only be considered good in SOME situations.
-They have a Role to perform like many other champions and abide by the rules of that Role.
-Positioning is punished the most on the ADC role.
-And the consequences of bad positioning by ADCs define (most of the time) the win or loss of the team fights/ games.
This is my 2 cents.
Downvote and keep your theories that Crit ADC is a broken class, when you could just learn how to deal with them... most of the times there is 1 in each team.
But ppl normally don't like to learn.