The the column width is just about ideal at approximately 77 characters per line.It could be slightly wider without detracting from the readability, but not all that much. [1][2]
The negative space left and right is to ensure an optimal column width. If there is nothing important to place to the sides, anything added there would serve only to distract from the flow of article content. That is to say, filling space for no reason is unreasonable.
Pagination is its own thing, and I won't comment one way or another on that.