You're a long term Apple enthusiast but you claim you had "no warning of such drastic change". Seriously?
I agree Apple should allow users to roll back to previous versions if they wish, but you contradict yourself a little within two posts.
Despite the stupidly ironic or condescending replies to his plea, the OP DOES HAVE a point.
And why? Because the ordinary user, not used to participating in forums such as this nor having time to read long descriptions of what has been "improved", is prone to tapping a single button that then leads to the upgrade process in his own iDevice. Call it lack of attention, mistake, whatever - but one should still have the possibility to roll back.
In fact, this happened a couple of days ago with my father (decidedly not an IT-savvy person), who saw Apple's pop-up message for iOS7 and innocently tapped on it in his iPad, only to discover later that he had a totally new UI and so on. He is not exactly complaining about it; but the sheer number of changes (such as Safari page handling) makes for a considerable learning curve when it comes to people who are not used to pushing buttons.
Indeed, Apple has NEVER blocked the possibility for anyone to roll back OSs (on Macs) unless the device itself already came with whatever latest version of its OS (or depended on System Enablers in the case of earlier System versions). Apple's decision to stop signing iOS 6 is absolutely arbitrary and has nothing to do with security or compatibility concerns.
At the very least, they should allow customers to use the immediately preceding version of ANY OS (again, unless the device itself cannot use it). This possibility makes sense EVEN if someone is totally knowledgeable or aware of the upcoming changes, which can NEVER be totally perceived or understood until you are using the new OS yourself (the threads about "hidden" iOS7 features are just further evidence of that).
So yes, the OP definitely has my support on this principle.