Settings > General > Accessibility > Bold Text = ON
problem fixed.
Not even close. If you have the option off the typography is too fine for lots of people, if you have it on everything's too bold and it frankly looks hideous.
Apple know that typography is important. It's a very intricate subject. Apple seem to have delivered a system that is either too thin or too bold for a large number of their users, which shows that they've just got it wrong on this occasion.
Also people saying "you chose this" (as in the first few posts) are wrong. You couldn't make an informed choice because you couldn't get a good sense of the new OS without updating.
It's like me sitting in a mansion, asking you teasingly "want a new house?", then when you say yeah it turns out that I'm giving you a shed in the middle of woods.
That said, from a technical perspective rolling back is totally out of the question. What about all the security holes that were fixed (you know, the stuff we can't really see)? What about all the new frameworks that Apps are going to be built to depend on? They want everybody making Apps using these new iOS7 frameworks, so they need as many people as possible to be on it. More people clamouring on to iOS6 will just split the platform and turn it in to Android.
The solution, IMO, is for Apple to listen more. They can't be stubborn and refuse to alter their design direction in the face of such widespread criticism (and it clearly is widespread), if they want to create a mainstream platform.
I think we'll see an iOS 7.5 update around January which will address a lot of these design issues. It won't add new features; that will be saved for iOS8, but they will feel a need to remedy these issues before they cut off another boatload of iOS devices from support.