Their is a HUGE difference between a season overtimes and playoff overtimes. A 1 game lead vs a 1 point lead !!! Ask all the players if they want to play a 20 min overtime who will finish at 12h00 in Vancouver and play the very next day at 19h in Florida??? There is no way it would work.
Shootout is better for TV, better for the schedule, better for the fans (I've been to the game in Bell Centre against Edmonton, and i would have been VERY disapointed if the game has ended after the OT).
Bringing shootout make you put more snipers in the lineup instead of goons too.
And i forgot about the players. They would be tired after 70 mins of play, so they would be less concentrated. The game would be more disconnected. The most you get tired, the most you have chance to be injured. You would see a lot more injuries and many less players diving in front of a shot as we see in playoffs.
Sudden death OT is good only for the playoffs when it's all about courage and toughness.
Here in Montréal, we love hockey and a draw isn't so bad, but in Columbus or Tampa Bay, shootout is way better and fans might like it much than a draw.