The quick answer is that we cannot say, due to nondisclosures. iOS 6 is just available in a closed beta for now. However, I probably can make comments on what I have read on the web.
Here are some of the rumored improvements:
Remote Debugging: It looks like there will be a way to have a desktop debug session hooked up to a device. This will make it much easier to debug on iOS devices.
<input type=”file”>: This will allow interaction with local files on the device. I’m not sure whether this will be more than just photos. It should get rid of the need to use PhoneGap for some apps.
Improved Audio: This would be great, if true. The current audio on iOS is not great.
App Cache increased from 5 to 25 megs. Lets you do much larger apps!
We will continue to watch for more new stuff in iOS 6. We will try to make sure that as many of the new features as possible will be available to App Studio users when OS6 is actually release.