Ok, here is my assessment of the posted solution.
First, the instructions posted on getting the device into recovery mode are incorrect. You need to connect your iPad to your computer via the USB cable, power the unit off, and then press and hold both buttons to turn it back on, and it will enter recovery mode.
Second, It does appear that the OS is ever so slightly snappier on a fresh boot, but still nowhere, and I mean nowhere, as responsive as iOS 7.
I have chosen to set the iPad up as new, rather than restoring a backup to evaluate the system from a pristine load of the OS.
When trying to put the stock Apple apps into folders, there is noticeable lag when trying to move the icons into folders. When trying to change the names on the folders, the system is sluggish to respond with the keyboard.
After going into the app store, and reloading some apps (17 to be exact), I have found the system to be less than responsive and the app store struggles to keep working while the apps load in the background. I set the unit aside to allow it to load the apps without me further taxing the system, and now I am getting errors loading the selected apps, after selecting "Retry", the apps seem to finished loading, the system is clearly struggling to load the the applications. Now yes I know that this may be related to internet connections and the App Store itself, so I have attempted to load the same apps on my wife's iPad that was never upgraded from iOS 7, no issues there. If you are curious, it took better than 30 minutes to load the apps on my iPad2, and my internet connection speed tested out at 41/11 from Seattle to Las Vegas.
When navigating the OS, and using the browser, it's a click or tap, pause, continue. I am amazed at the latency in basic navigation.
The last test I performed, after waiting for all the apps to load, and rebooting the iPad, was to start the game Plants vs. Zombies 2. This is a test of patience. After a short period the game loaded and signed into Game Center. This is a huge improvement over the previous load time before installing the OS fresh.
All in all, the posted solution by Star Traveler is not going to restore the performance of your iPad 2, to iOS 7 levels or anywhere close. While the iPad is functional, it is not an experience that anyone should be proud of.
If you are still on iOS 8, or 8.0.1, then 8.0.2 will be a minor improvement from where you are. If you are having significant functional issues with your iPad since loading iOS 8.x, it may resolve some of them.
I must say that I am still less than impressed by the performance of iOS 8. I am even less pleased that I have needed to reload my iPad twice, in two different ways, to correct issues. Any yes, both times I wiped the iPad, it was set up as new.