Look, there is simply no chance that Apple is going with flat UI and color coded icons. The changes wont be extreme, Apple is not going to fire their graphics department so they can implement flat squares. Yes they will get rid of the kitch.
Think how many peoples' apps would break if they went to Flat UI, think how many users they would alienate? Think how iOS is supposed to have some kinship with OS X design ethos. Is anything in OS X flat?
Linen is staying. Drop shadows, gloss and rounded corners are staying.
Apple isn't going to go Metro-flat, but the next version of iOS will definitely be flatter.
The OS X comparison you are making is bad because before now Jonathan Ive wasn't in charge of user-interface design, Scott Forstall was. Both of them have drastically different aesthetic design tastes.
It's well known that Jonathan Ive finds textures such as the linen and corinthian leather tacky. They will be removed.
Think how many peoples' apps would break if they went to Flat UI, think how many users they would alienate? Think how iOS is supposed to have some kinship with OS X design ethos. Is anything in OS X flat?
Linen is staying. Drop shadows, gloss and rounded corners are staying.