Whatever comes of this, I can't shake the feeling that the flatlander community won't think it goes far enough, where everyone else won't care at all.
Pretty much. A gross majority (which is to say a very vocal minority) of the flatlander community are not real designers or aren't designing within the same context of something like an iOS.
If iOS 7 looks different, I'd venture it won't look different in the way we expect. I can't really think of a single example of Apple historically following the lead of others with their UI styling. (Happy to be called out on this, though).
Personally, I'd really just expect (and love) a slight toning-down, just as Mac OS 10.3/10.4 flattened and toned-down the Aqua look. Get rid of the pin-stripes, make some of the drop shadows and gradients a little more restrained etc.
honestly, im a bit concerned it's already late to the flat party, but i trust Jony Ive to deliver. A lot of flat apps I'm seeing are starting to all blend together in my brain.