"The NHL first discussed the idea of larger nets two years ago, when players and league executives met to debate ways of increasing scoring and opening up the game."
"The topic was revisited briefly in June when general managers met in Ottawa." [Luongo vows to quit over bigger nets].
How much would 1" change in net size (on all sides)? So what would happen if we moved the left post by 1" and the right post by 1" and increased the hight by 1"?
Since the NHL records how many goalposts (and crossbars) there are, we know how often the puck hits the 2 and 3/8th inch posts.
Last season the puck hit the frame 1480 times. So moving the post by 1" would mean taking the shots that hit the first 1" from the inside and counting those as goals and the pucks that hit the other 1 and 3/8th inch would still be posts (plus all the new posts) [simple logic, "works well enough"]. Essentially this would convert 1/(2+3/8) of the frame hits into goals or about 623 new goals per year for every 1" change in net dimensions. So it would take a 2" all around the net change to increase scoring per game by 1 goal.
Of course this is assuming goalies and teams don't adjust to the new system. Goalies would attempt to cut off shots even more (quite an adjustment for a goalie like Luongo).