The Starcraft II multiplayer ladder had recently concluded an eventful season 3, having been locked last October 10 to let players use up their bonus pools and for Blizzard to prepare for a new format for season 4. The season lock means that you can no longer be promoted or demoted from the league you’re currently in, so you can fool around if you don’t care for your MMR. You can still practice in that league, but you won’t be able to move from there until the new season swings by.
It’s still a good time to move up the ranks if you’re not in the league top 8 already. The higher you are by the end of the season, the better chances you get in getting promoted in the new season. Whatever you did during the season lock will count in your placement match leading to the new season. Therefore, if you did fool around and lost tons of times during the lock, then you’ll most likely get demoted to a lower league as a result. For those who have played during season 3, one placement match is enough as the MMR from the games played during that season will be considered. If you have not played at all during season 3, then you will be given five placement matches to gauge your skill level.
Ladder season 3 had seen many changes, including an updated map pool and new patches that turned the current metagame around. Various balance changes have occurred, including the nerfing of Hellions and Infestors while Immortals and the Mothership had been slightly buffed. Even after over a year, balance issues are still the most controversial at the moment. The new maps have also had players scrambling for solutions to their problems in the game as they aren’t at the same level as Metalopolis, but at least they had removed Scrap Station.
The new format for season 4 features a much shorter length. From now on, each season will only last for around two months to encourage people to play much more. What usually happens is that most people would play during the start of a season, then they stop for a bit in order to build up a bonus pool before gunning it just before the season lock to get promoted. Also, grandmaster league placement will be shortened to one week from the previous two weeks to accommodate the much shorter season.
The opinions on this shorter format has fans divided in terms of how much this game will be played each season. While Blizzard may be right in saying that we can see more activity as a result, others say that the greater frequency of new seasons will see even more inactivity since not a lot of people would want to redo their progress again and again. Perhaps this does sound like a pessimistic way to look at the new format, but Blizzard is pushing through these changes anyway, regardless of anyone’s qualms.
We shall see if things do change for the better in Starcraft II. Season 4 will start sometime during the last week of October, from 24 to 28.

