Riot Games weren't content with just announcing the venues for the MSI and Worlds today, but they also posted an extended update on the MSI and its format this year, detailing the seeding, format, and implications of the tournament.
A big change this year is that regions will be seeded based on past results over the previous two years of MSI and Worlds, and they've justified this two year sample because "within a single year, there can be considerable variance in competitive results, so we don't want to solely rely on the most recent year of performance to determine seeding. For example, although Albus NoX Luna from CIS performed extremely well at Worlds 2016, it was their first appearance at an MSI or Worlds. We don't believe it fair to use solely that performance to assume that CIS is stronger than LMS, who didn't have a team make it to the Quarterfinals, but have performed well at previous events."
They haven't gone further back than two years, however, as there have been big changes since 2014. Once they had determined the two year window to look at then, they looked at all regions and compared results, using three principles to distinguish similar results. Firstly, they prioritised Worlds results over those at MSI, then they prioritised recent results over older ones, and then evaluated tournament results by stage achieved. Here are their findings:
What these findings mean is that, because LMS and NA haven't played as well as CN, EU, and KR, especially at both Worlds, they will enter the Play-In stage of the MSI, in the second round. CN, EU, and KR will instead be auto-seeded to the competition's group stage, which consists of six teams. Joining NA in the Play-In stage, but at round one instead, will be the number one seed from BR, CIS, JPN, LAN, LAS, OCE, SEA, and TUR. This removes the Wildcard status, and each region is now being considered individually, meaning their performance will affect future seeding too.
Three teams from the Play-In stage will then face CN, EU, and KR in the Group Stage, with six teams taking part in a best of one double round robin. The top four teams will then go on to the knockout stage. These results will subsequently affect the Worlds seeding, just as the previous results affected that of MSI. The top regions at MSI will then early the top four seeds at the Worlds Group Stage, and the highest ranking of those in MSI's first round will get an additional seed, "their #1 seed will start in the Group Stage, and their new seed (the #2 seed from that region), will start in the Play-In Stage."
What do you make of these format changes? Are they for the best?