As it stands now:
American League
East : Blue Jays, Devil Rays,Orioles, Red Sox, Yankees = 5 teams
Central: Indians, Royals, Tigers, Twins, White Sox = 5 teams
West: Angels, Athletics, Mariners, Rangers = 4 teams
Total Teams in the American League = 14 teams
National League
East: Mets, Braves, Marlins, Phillies, Nationals = 5 teams
Central: Astros, Brewers, Cardinals, Cubs, Pirates, Reds = 6 teams
Western: Diamond Backs, Dodgers, Giants, Padres, Rockies = 5 teams
Total teams in the National League 16 teams
How is it that the National League allows this disparity to continue? Just the fact that there are two less teams in the American League translates into, less travel time for players, as well as two less teams to contend with. This combined with the accepted disparity the Designated Hitter creates, (pitchers in the American league never have to come up to bat!) attributes to the fact that the American League will deal with less stress and fatigue. The addition of Inter-League play non-withstanding.
Since 2006, I've been hearing the grapevine chatter about how the American League is just superior. Well it's no wonder, look at the slanted disbursements of scheduling. The fact that there are two less teams in the American League to compete with than the National League makes for an unfair advantage. The American League as a whole contends with the opportunity to play more and risk less. The fatigue factor that travel and day to day ball playing create is heavier in the National League. This affects travel, conditioning, their pitchers come up to bat, which causes more wear and tear on both the pitchers and their team. In turn it trickles down to the the Minor leagues where the American League has to worry less about the amount of players that may be called up to play against their team.
It is so unbalanced for a sport like baseball which is statistically driven, to continue to perpetuate such an askew foundation for fair play. It creates and substantiates an unbalanced playing field. Which will always teeter its advantage toward the American League.