It appears they're now using Helvetica Neue Light instead of Helvetica Neue UltraLight.
Ahhhhhh! This kind of cluelessness is maddening.
Apple already didnt use the ultra light variant almost anywhere. Clock in the lock screen, calendar icon, thats it, more or less. All other fonts were already not as light as ultra light. Ultra light is mostly eye candy and decoration, not meant to be used at small sizes and not meant to be used excessively. And Apple already didnt.
In iOS7 Apple uses different font weights depending on font size and semantic meaning (headline, subtitle, body text, etc.). On a given screen there might be many different font weights of Helvetica Neue present, from thin over light, regular and medium all the way to bold. Those different weights were made to optically fit each other. (By the way, this is actually super-awesome and Im unaware of any other UI doing it. Heck, today even many places where you might expect proper typography dont do it, for example pretty much all websites.)
Now, I would say that Apple picked to flimsy weights overall but Helvetica Ultra Light was never the problem.