Re: It's that time again: Smartphone upgrade!
As far as I am aware, rooting does not require you to replace to OS. Rooting is merely a way to let you change settings that you aren't normally allowed to change.
And no, Nova launcher doesn't allow you to uninstall the apps that you would normally be prevented from uninstalling. it's just an app that lets you change the appearance of the homescreens and the app dock.
I've been using the Next Launcher...really impressive.
It is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring. Carl Sagan