I'm just an outsider, but I've been with OS X since the early days. Oh those were such cool days.
As a product guy, I keep reading between the lines that way too much leeway may have been given to Jony Ive (I have nothing against him and like his industrial design). Someone that needed to have said No, didn't though. Ultimately this falls on Tim Cook.
This may ultimately turn out okay for Apple but I've been around this block long enough to know that the initial user input is a great indicator of a product's success. The problems of this rollout do offer a learning experience for anyone in design or product decisions.
Never think, you know better than users. Never stop listening to what users are telling you.
Listen and act.
I hope Apple is willing to listen to what many users are saying about flat design and colors. I see a few who enjoy the design, but overall the sentiment is negative and for very valid reasons.
When user experience and usability suffer because of someone's aesthetic choice, there is a leadership problem.
Flat design is a trend that forces users to "have to figure it out". It's poorly implemented in most cases. A website that was linked on HackerNews, showed before iOS7 apps compared to post iOS7 apps. Most of the comments favored the pre-iOS7 apps. Flat design harms the user experience and the whole reduction of affordance increases cognitive load unnecessarily.
Someone should have said "NO" or at least, "Not this way."