It depends where do you live. If in EU it should be fine. If not I can find a rom good for your location.
No, flashing custom rom does not require rooted device.
I think you don't have to do the backup as you'll be able to just update it again ...
You can flash stock kitkat with flashtool. I should have stock EU . 157 rom somewhere on my pc and can upload it if you want.
Flashing stock rom is pretty easy. Watch a tutorial or something. I can help you a bit more when back home.
Back to yo...
Got this phone just as I was going to London. I was able to shoot some pretty nice pics ! :)
WARNING!! These are mostly 20.7 MP photos I've made an album on imgur and these may suck quite a lot of your net when loading.