Crit adc is in a bad spot so you nerf them?

I looked at the proposed changes to crit adc and they are definetly getting nerfed. Didn't riot say that they were weak and needed help?

Currently: As of right now you can go Storm, RFC, and IE for 9k gold giving you - 60% crit, 130 AD, 65% AS (208 Damage per attack average) Or you go IE, Zeal, Competed zeal for 7.5k gold gold giving you - 90% crit and 70 AD, ~45% AS (133 Damage per attack average) Or you go IE, Zeal, 2 Completed zeal for 9k gold you get 120% crit, 70 AD, ~60% AS (140 Damage per attack average)

Proposed change is: IE, Completed Zeal, Completed Zeal (Shiv & RFC) for 9k gold - 75% Crit, 70 AD, 65% AS (131.25 Damage per attack average) * they didn't list stormrazor so I cant calculate it in round 2

Questions:

1. Am I missing something since riot has stated on beyond the rift that crit adc have little agency in the game since they get the 3rd item soon as the game ends on average with the 29 min game time?
2. How is this going to help them scale more evenly in the mid game when it is a straight damage nerf? Is this part of a larger plan to overall nerf damage across the board?
3. Why is 100% crit not being used as a standard to help balance crit based adc? It will produce consistent results in the late game since you just removed the RNG factor
4. Does the RNG of "who crits more in a fight" the direction we want to take the game back to?