yeah well that's another thing that pisses me off about the ICS update. I was never notified by verizon or motorola that my phone wouldn't function properly without a factory data reset after the update. That's not a minor detail. If I had known that, I would have never accepted it in the first place.
Smartphones are really just computers that can make phone calls. In fact, they our Bionics are likely just as powerful, it not moreso, than desktop computers of 15 years ago. Would you have upgraded, say from Windows 95 to Windows XP without refortmatting? That is essentially what we are talking about.
Just as computer manufacturers and software makers don't tell us we need to do clean installs, people have learned over the years that the best performance comes with it.
Stop and think about it. We had GB on our phones that wouldn't even use both cores of our CPU's. Many apps never got updates to ICS compatibility, and those that had, some people never updated those apps. So any apps you may have installed under GB, even if ICS compatible, were working totally different because of the underlying OS. This is likely the performance hit.
And honestly, an FDR is relatively painless and easy to do. If you have apps that have user data saved to the phone, such as some checkbook managers for example, you merely save the data file the SD card, and you pull the SD card when you do the FDR, and once the FDR is complete, you merely redownload your apps from the Play Store and reimport your data. yes, it takes some effort, but ANY electronic device is going to take some sort of maintanence effort.