Note: All statistics are good through Worlds 2016 semifinals
Similar to many competitive video games, League of Legends employs a patch system in which the game developers can tweak and adjust certain characters in the game to make them better (buff) or make them worse (nerf). The entirety of Worlds 2016 is being played on patch 6.18 which was tuned specifically for competitive play. Even with all the tuning, some champions still come out better than others.
In League of Legends, there are 132 available champions that can be selected. In the 72 games played at Worlds 2016, 56 were either picked or banned at least once. Of those 56 champions, 33 have been picked or banned in at least 10 games. When 16 champions get picked or banned in each match, the champion pool starts shrinking fairly quickly.
Highest pick/ban champions -- 2016 League of Legends World Championship
*Games picked + Games banned/total games
Fun fact: Gangplank was the only champion to have a 100 percent pick/pan percentage at Worlds 2015
There are many reasons a champion may be picked or banned in any given game.
Sometimes it has to do with strategy; if a team starts putting together a pick composition looking to roam for individuals kills, it may ban a champion like Tahm Kench who excels at getting his allies out of dire situations.
Occasionally, champions will be banned because a team is targeting a certain player. Some of the most famous targeted bans came in past years against Henrik "Froggen" Hansen (Echo Fox), who excelled at playing Anivia and would even select her when not popular, or not "in the meta."
The most common reason a champion gets banned is because of its raw power, which can be expressed in champion win percentage.
Champion win percentage* -- 2016 League of Legends World Championship
*Min. 5 games selected
What does all this mean for the finals on Saturday?
Mid/top
There are two extremely flexible positions in this matchup in mid-lane and top-lane. In SKT T1's 15 games at Worlds 2016, Lee "Faker" Sanghyeok has played eight different champions and has notched a win with all eight. In Game 4 of the semifinals, ROX Tigers utilized all three of their bans on mid-lane, taking away Syndra, Ryze and Cassiopeia from Faker. Faker adapted with ease, picking up Zilean and proceeding to go 5/2/5.
Most unique champion wins -- 2016 League of Legends World Championship
*Eliminated in semifinals by SKT
Samsung Galaxy mid laner Lee "Crown" Min-ho has shown similar flexibility playing five champions through 12 matches.
Worlds 2016 has featured a top lane that has become a catch-all, with teams tending to build a team strategy and then picking a top laner that fits that composition. SKT T1 has featured eight different champions in 15 games in the top lane, not because of targeted bans, but because top laner Lee "Duke" Ho-seong's champion pool will fit the needs of the team strategy.
Samsung Galaxy's Lee "CuVee" Seong-jin has also shown flexibility and mastery of many different champions, winning with five champions in 12 games.
While it is possible bans will come from these two lanes, they are more likely to be strategically focused (Ryze) or based on raw power (Syndra -- 63 percent win rate) than on trying to intentionally cut down a player's champion pool.
Jungle
The jungle is in an interesting spot for these two teams in patch 6.18 as the position has seemed to devolve into Nidalee (85 percent ban rate) and Olaf against every other jungler. While Olaf sports a 50 percent win rate, he has been picked in 34 out of the 72 games played which is second only to Karma (39).
In the semifinals, Olaf and Nidalee both had a 100 percent pick/ban rate. The only two other junglers to see play were Lee Sin and Elise, both of which fall off significantly if the game goes late.
Jungler win rates* -- 2016 League of Legends World Championship
*Min. 10 games played
Samsung Galaxy's only loss at Worlds came when its jungler Kang "Ambition" Chan-yong played as Elise, for the first and only time in the tournament. If both Nidalee and Olaf were to be banned, Ambition would probably fall back on one of the other two champions he has played this Worlds in either Rek'Sai or Skarner.
SKT T1's jungle has had both ups and downs at Worlds 2016. Both its junglers, Kang "Blank" Sun-gu and Bae "Bengi" Seong-woong, have put up great games but have also struggled at times. Blank is 6-3 at Worlds 2016, and all three of his losses have come using Olaf. Notably, when Bengi plays Jungle for SKT T1, he is 2-0 using Olaf. Overall, SKT T1 is 7-1 when one of their junglers is not playing Olaf.
SK Telecom T1 Junglers -- Blank and Bengi
Bottom lane
One of the most overlooked roles came under the spotlight in the semifinals when Miss Fortune, a typical AD carry, was picked into the support role three times. She went 3-0 and proceeded to draw bans in three games. Ashe, Miss Fortune's wombo-combo partner, was picked or banned in seven out of eight of the semifinal games after being picked or banned in only three of the previous 64 games. Ashe went 5-1 in the semifinals, her only loss coming in Game 4 against SKT T1's poke composition that included Nidalee, Karma and Zilean.
AD carry win rates -- 2016 League of Legends World Championship
*Second lowest champion win-rate at Worlds 2016 (min. 10 games)
While Ashe put on a show in the semifinals, Jhin has been the primary AD carry for many teams, garnering the most wins (20) of any champion at Worlds 2016. Even with Ashe's newfound presence in the semifinals, she was still picked or banned in six of the eight games.
Both Samsung Galaxy's Park "Ruler" Jae-hyuk and SKT T1's Bae "Bang" Jun-sik have not lost a game using Jhin at Worlds 2016, going a combined 9-0 using the champion.
Of the other options at AD carry, neither Ruler nor Bang has shown that they are willing to play Lucian, leaving Caitlyn, Sivir and Ezreal. Neither team has had spectacular showings with Ezreal, going a combined 5-3 on the champion while maintaining a 17-2 record with all other AD carries.
In the support role, SKT T1's Lee "Wolf" Jae-wan has shown that he is most comfortable on two champions: Zyra and Karma. While he has played and won on other champions, he has not strayed from the former two unless they have been picked or banned away from him.
Samsung Galaxy's Jo "CoreJJ" Yong-in also tends to favor Zyra and Karma playing six of his 10 games on those champions. CoreJJ is also the only undefeated player in the Worlds 2016 Final, as he was substituted out for Kwon "Wraith" Ji-min in Samsung Galaxy's only loss.
Bottom line bans
Look for bans of Nidalee, Syndra, one of Miss Fortune or Ashe, and then either a focus on the jungle (Olaf, Lee Sin, Skarner) or bot lane (Zyra, Karma, Caitlyn, Jhin). Faker's Ryze may also be worthy of a ban for SSG, as the champion offers Faker an extreme amount of playmaking potential.