It looks like Southwest Airlines will be making a few changes to their Rapid Rewards program. They posted this announcement on their website:
We created Rapid Rewards® because we think you deserve to actually feel rewarded. And, from time to time we must make some updates to our program. Beginning April 17, 2015, the number of Rapid Rewards Points needed to redeem for certain flights will vary based on destination, time, day of travel, demand, fare class, and other factors. However, there are still many flights which will stay at the current redemption rate. And don’t forget that when fares go on sale, so do the points needed for redeeming for a reward flight on those fares.
What does this mean?
To me, it looks like they are changing their rewards program from a fixed-value points system to a variable-value points system. In other words, it'll cost you more points to fly their more popular routes.
That also means your RR points won't quite get you as far come April 17 - as they do today. And that is a good lesson to remember: if you play this game don't use points as a savings account. After you earn points burn them. Earn and burn. Hoarding points will get you nowhere. They'll just lose their value.
If you fly a lot of Southwest's most popular flights, this change will hurt you more than the other person. Otherwise - you don't have much to really about.