Tips to make the Nexus 4 a productivity machine?

Hi everyone,

just got a nexus 4, it's my first time with Android.

First thing I notice: I can't seem to make folders or arrange apps the way I want. Maybe I'm dumb but with iphone I just dragged and dropped, whereas now here I am googling tutorials for Android. And the tutorials I find are all about how to root the nexus 4. But I'm just trying to organize a bunch of apps I downloaded from the play store.

so I have a bunch of questions for android experts:

First question : why would you root the nexus 4? I thought it had already stock android? what's the point?

Second question: how do you arrange the apps ? I want to put the social media apps on one slide (fb twitter etc), the media apps on another (the verge, ny times, etc) and so on. when I drag and drop it tells me the home screen is full.

Question 3 : the widgets are a little raw and ugly on the nexus 4 with stock android... how to arrange them? is there a way to skin the phone without making it too slow?

Question 4: what is nova launcher and apex launcher? I see they are best selling apps but what is their purpose?

Question 5 : is it possible to play gapless flacs streamed to the nexus 4? I'm gonna stream them from a server, either with foobar or plex media server because I took the 8GB version of the nexus.

Question 6: what's the best way to edit word documents on the nexus 4?

question 7 : any good apps for writing?

question 8 : best way to view pdfs on the nexus 4?

9: any other tips to turn it into a productivity machine?

Thanks for any insight.