It's not a lost feature, but it could be considered a lost opportunity. It's also a problem that Verizon and Sprint created, which they could solve by changing their LTE network setup -- clearly what Apple thinks should happen.
The lost capabilities in the iPhone 5 are all ones that money and/or time will resolve. But if any are critical to you, be sure to time your upgrade with the availability of the solution -- and your ability to pay for it.
One piece of good news: I can attest that Apple's new EarPods earphones are really nice-fitting and sound very good -- and they work with any iPhone, iPad, or iPod you already have!
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