What?
How many wired headphones can I use that are not iPhone certified. Single ear Bluetooth headsets? Where's the difference? Apple's not going to go broke by allowing A2DP headsets to pair with the iPhone when so many people use third-party earbuds and BT headsets already.
Also, there are plenty of details about Bluetooth that are not mentioned on the website. I don't see where the specs say, "supports Headset Profile (HSP)" but Apple sure a heck makes a bluetooth headset for iPhone. In fact, it doesn't mention any supported profiles. The exclusion of A2DP on the website means nothing and it's inclusion would not necessarily be worth mentioning at WWDC.
And for those asking, yes Bluetooth 2.0 + EDR can handle A2DP via software upgrade.