Blizzard has revealed plans to change the matchmaking settings for ladder season 7. The changes will be an experiment on laxing the range of skill that a player can be put up against. Right now, people are being matched incredibly close to their analyzed skill level, thus resulting in very close games where both players must be on the top of their game. What Blizzard is aiming to do with these season 7 changes is to see how players will feel when periodically facing others of slightly lower or slightly higher skill level.
As a one-season experiment, we will be slightly relaxing the matchmaking settings in Season 7 to introduce more variety into the ladder. In practical terms, this means you won't always be evenly matched with your opponent. You'll regularly compete with players at slightly higher or lower skill levels, resulting in what should be a more well-rounded experience. These adjustments to the matchmaking system could also result in some players earning faster league promotions for stringing together wins against higher-ranked opponents.
Depending on fan feedback, Blizzard will be making more adjustments to the matchmaking settings past season 7. Be sure to let Blizzard know about any faults or improvements to the matchmaking system, to create a finer-tuned matchmaking experience.
Battle.net - Upcoming Changes to Matchmaking