I just got a 5 so I'm new to siri, but I'm experiencing the same problem on beta 3. After researching it I found that a lot of people have had this issue since the introduction of siri, so I'm not sure if it's an iOS 7 related problem...
The ability to change system settings is the main one I miss, and that was in Beta 1, but not any more. I was using that heaps, along with getting Siri to read my incoming texts while I was driving.