Give me some specific iOS examples of what was tested internally that the public never knew about and was released to our surprise.
We would not know about then, would we?
and again, what would 4.3 need to be tested for?
The article says
Unlike 4.2, which introduced a host of new features (like AirPlay and AirPrint), 4.3 will include just one major addition: subscription billing, which would allow content providers to charge weekly, monthly, or annually for subscriptions
An update is possible but the question asked was about iOS 4.3...which would indicate a pretty substantial update to the operating system to receive the .3 moniker. 4.2.2? Maybe, especially with such a small update, but even still...i doubt something like that would just be dropped with no word, especially so close to the 4.2.1 release.