You don't need to follow tech news or be a member of tech forums to see - in the update description, right above where you press download and install - that it says there is a significant change to the user interface, and to go to apple.com to see the iOS 7 info link on the front page of their website.
And it says what? There is a beautiful new design? OK, fair enough... I don't think that it is beautiful, but I checked before I updated, didn't like it, didn't update...
But that's me and you... A friend of mine, who didn't check, as she never does, because until now there wasn't a need to check, updated and now I just get phone calls asking me... "What is this, where is that thing that used to be there..."
And that is the way most users update... We, here, on the Macrumors forums are a minority, we talk and discuss about changes months before they happen...
But, that's just us...
All I'm saying... If the change is so big, and it is, just leave an option to go back for a while longer...