The netting pretty much guarantees that the puck stops dead when it hits it and then the puck takes a second or two to fall, which gives the forecheckers more time to get to it before the defenders can clear it. Teams would purposely start lobbing dump-ins to the netting instead of to the cross-corner in order to have a higher success rate of keeping the puck in the enemy zone.
Defensemen would be caught waiting, almost like the punt receiver in football, except they don't get to call fair catch so they'd be getting smoked every play.
Overall, you'd see a lot more pucks go to the netting, more injuries to defensemen and likely more pucks that miss the netting (on the sides) to actually go into the crowd.
Bad idea.