Baseball is all about getting hot at the right time. Your bats go cold at the wrong time and you're out.
I have no problem with the playoff format. Basically, you have two central division teams winning a division that are worse than many wild card teams. Heck, the Rangers were basically tied for 1st anyway, just lost a tiebreaker.
The D-Backs were quietly dominating most of the year but didn't get much attention. They really scuffed down the stretch, but again, they heated up at the right time. In a way, you want to hit your slump late in the year.