The 2014 Royals postseason run is a good illustration of how fast baseball has changed. The last time that an AL Central team came out of nowhere to sweep the ALCS and go to the World Series was 2006.
The Royals weren't nearly as bad last year as the Tigers had been before 2006, but they're both big surprises. In 2006, the Tigers had the #1 team ERA in baseball at 3.84, and had 6.23 K/9 (ranked 23rd). The 2014 Royals ranked 12th in team ERA at 3.51, and had a K/9 of 7.25 (ranked 24th).
How would the 2006 Tigers have ranked in 2014? Their team ERA of 3.84 would have been ranked 21st. Their K/9 of 6.23 would have been ranked 30th. In 2006, the Tigers had a somewhat dominant bullpen, with a Batting Average Against of .242, which was ranked #2 in baseball. In 2014, that would have been tied for 19th. The 2014 Royals had a BAA in their bullpen of .235, which was good enough for 11th in 2014, but would have been ranked #1 in 2006.
Yes, 2006 was a while back, but it isn't ancient history. The only remaining player on the Tigers from the 2006 Tigers is Justin Verlander, but they're still on a run started by that team (although it might be petering out). What were considered good pitching stats in 2006 would be considered mediocre at best today, and sometimes downright awful.
The Royals also ranked 14th in runs scored this year (651), which would have ranked dead last in 2006. The game has changed and the Royals are a great indication of how quickly it has happened.
Since the last time that a road team won game 7 on the road in the World Series in 1979, teams have been terrible without home field advantage. The National League has been particularly bad, especially teams that did well during the regular season. Since 1979, the NL is 3-15 when they don't have home field advantage.
NL without home field since 1982
92 wins and under (3-4): W ('03, 06, 08) L ('83, 89, 05, 07)
93+ wins (0-11): ('85, 87, 91, 93, 96, 98, 00, 02, 04, 09, 13)
It is obvious why not having home field advantage could be a problem, especially if the series goes 7 games (road teams are 0-9 in Game 7 since 1979). It is less obvious why teams that had better regular season records would struggle. It is possible there is something in the psyche of a real underdog (like the '03 Marlins and '06 Cardinals) that would help them in the postseason. Whatever it is, the trend is clear.
Since 1997, no NL team has won the World Series with more than 94 regular season wins while no AL team except 1 (2000 Yankees) has had fewer than 96. It might be somewhat irrational, but it has been happening for a long time now. NL teams with 93+ wins struggle in particular against AL teams with more than 96+ wins, going 0-7 in the process.
Obviously, this is going to be broken at some point. Considering how often teams win Game 5 on the road in the LDS (Tigers did it three years in a row), it is only a matter of time before a road team wins Game 7 of the World Series on the road again.
Let's say for the sake of argument that this is all somewhat predictive. What would it mean this year? Well, it would mean that the 96-win Orioles would have some serious wind at their back if they were to face the 94-win Dodgers or 96-win Nationals. Now, the Orioles might want to avoid facing the Cardinals or Giants for other reasons (like these two teams combining to win 3 of the last 4 World Series), but this might not hurt.