The "most exciting play in baseball" has long been the surname of the triple (though some would disagree as to its accuracy). Every time a player steps into the batter's box, there's a chance for one, giving fans a minimum of 55 opportunities per game to see the sport's most exciting play.
The most exciting play in football is probably a kick return for a touchdown. I don't have the numbers on it, but would estimate that between the two teams there are on average at least 15 kicks in any given game, giving fans plenty of chances to see a punt or kickoff "taken to the house," as they say.
The most exciting play in the basketball is the alley-oop, which could happen on any trip down the floor.
The most exciting play in hockey, of course, is the penalty shot. In fact, I think that announcers are contractually obligated to use that moniker any time a penalty shot is awarded. Yet there were only 57 awarded in the 1,230 game 2003-04 season, which works out to about one every 21.5 games. For a game that's struggling to draw (and keep) fans, this limited exposure to the game's signature play is simply unacceptable.
Meanwhile, there has been exactly one tie in the NFL since 2001 (only 16 in League history), and the NBA and Major League Baseball play all of their regular season games until someone wins. By comparison, fans left NHL arenas 170 times without seeing a winner and a loser in 2003-04.
Finally, while sports highlight shows are jam-packed with homeruns, slam dunks and touchdown passes, hockey's goalmouth scrambles and slapshots from the blueline often have trouble getting air time.
Put it all together and the NHL's decision to add a shootout after a scoreless overtime in regular season games was a no-brainer (which is lucky for the League). Games will now be decided rather than merely over, and the most skilled athletes on the planet will be afforded the opportunity to show off their creativity and talent for all the sports-loving world to see.
I know the "traditionalists" (if we didn't lose all of them when the League first dropped the puck in Miami or named a team after a Disney movie) disagree. Hockey is a team game, they plead. The game survived 100 years without a shooutout, they point out. Well, actually it didn't. It died last year and has been reborn and it needs to expand its fanbase or this rebirth will be short-lived.