IIn my opinion, one problem is that Apple is extremely reluctant to ever admit a bug in the software. It would make it so much easier and less frustrating for all their users if they would simply post a bug list. The Bluetooth and car audio issue is well documented on the Internet.. For me, when I got my iPhone 6 and restored from a saved backup of my 5s, it worked in my Mercedes. But I have horrible battery life issues and several other problems as well. I restored and set up as a new iPhone. The Bluetooth in my car connection now became broken. Same issue as everyone else. I restored again from the 5s backup and my car Bluetooth works again. Go figure. But why can't Apple simply provide a list of known issues? It would make our lives easier. Also, Apple doesn't tell their support people about these bugs, either. So while Apple support is outstanding and incredibly helpful, they are kept in the dark like the rest of us.
You can, and should, send a bug report to Apple. Don't expect an acknowledgement, though. In the mean time, hope for a speedy release of iOS8.1 and a hope that the quality control manager for iOS 8 and 8.0.1 and 8.0.2 (and Maps) has decided to take an early retirement and is not overseeing 8.1.