In a way you're right.
Having a clean install is always smarter than a device loaded with apps of which only half is used.
Having a clean install makes your device more reliable and speedy.
Problem is after making a backup people tend to restore everything.
Of course you have backed up pictures and other important stuff.
What if you start by just adding the most necessary apps one by one?
Less is more, that also is true for mobile devices.
PS
Read what Sony explains about avoiding excessive battery drain.
There is a very good post in the FAQ as well.
