So, to recap. The ASU Team and the Summoner's Rift Design Team are different groups of people.

Back when Caitlyn was made, the original designer didn't have the code to impliment headshot as an empowered auto. So instead they made it a spell that behaves like an auto attack.

But, since then they've either figured out how to do empowered autos that way, or else they always knew and the original coder was a moron.

Either way, this state if affairs has led to bugs in the interaction between the auto system and the headshot system, allowing for certain combos and auto resets the designers never intended. It also makes Caitlyn buggy and have weird interactions every time new item effects are added.

The SR Design team has had this knowledge for YEARS. They've never fixed the base code. They've never gone through and adjusted it into Cait's design or power budget. They just let it sit there.

Finally, the ASU team starts in Caitlyn. One of their mandates is to fix bad code. They see the poorly coded headshots and go through the process of making it work as intended. They go to the SR Design team and explain this might effect the character design. But, the SR Design Team has never thought of it as more then a bug. They've never considered Cait mechanics or how to power budget for it, nor did they actually remove it either. Instead they tell the ASU team to go ahead with the change.

What does this story show?

1. The ASU team is doing their job exactly. They were sent in with the task of cleaning up Caitlyn's code and that's what they did.. everyone who plays her should be glad that they did their job correctly.

2. The Summoner's Rift Design Team are absolute failures, who throughout Caitlyn's lifespan never did any of the code work or design work needed to deal with Caitlyn. So when the ASU came around and it was clear that lots of Caitlyn mechanics had developed from a series of bugs, they had no game plan.

This is called "Production Debt" or "Design Debt". Taking shortcuts in game creation until they've stacked so high that any attempt to fix it becomes a shit show. They can't keep in the bad code because it's causing Caitlyn all kinds of bugs. But the SR Team should have done the work years ago to ensure when the bug was removed it wouldn't cause so much issues.

Conclusion: Don't shit on the ASU for doing what it's supposed to. Shit on the Designers for having ignored Caitlyn for so long that any attempt to make fixes to her would bring a house of cards toppling down.