Google Voice follows (or used to, at least) your advice, which led to endless frustration. You'd tap a notification to read a text, then have no way at all to get to the main screen of the Google Voice app. In Android 4.0, Google Voice has an app-specific back button that helps, but I think Google's advice on this is correct.
I'd think that the "typical" behavior would be to go back to what you were doing. I'm playing "Angry Birds", notification shows for text message. I click it, read the notification, hit back to get back to Angry Birds.
I don't see how inserting items between the text message and Angry Birds is a good idea.
What apps should have, is a way to always get to the apps main screen in the app. But changing the back button behavior seems confusing.
