Compared to other competitive games such as Dota 2 and League of Legends, Blizzard Entertainment's Overwatch does not have a roster nearly fleshed out enough to consider including a pick and ban phase to competitive matches.
League of Legends has a whopping 137 possible champions to choose from in any particular game, whereas Dota 2 follows with 112 heroes. Overwatch, in comparison, has 24 playable characters to choose from. You could ban every Overwatch hero from a match and still have at least 88 unique characters to play in either League of Legends or Dota 2.
This is the problem stopping Overwatch from implementing a pick and ban phase. Whilst the current roster is strategically diverse, there are just not enough heroes to choose from in order to allow bans without removing a sizable portion of the playable roster.
The idea of a ban phase is to prevent the enemy team from selecting a certain hero that you may dislike or a hero that is too strong at the moment. Traditionally, a pick phase, on the other hand, guarantees that you get your chosen hero before the enemy team can - however, in Overwatch, both teams can play the same heroes.
Overwatch can either decide to stick with its current choice of abandoning a pick and ban phase or make the change to implement it by expanding their limited roster to allow for greater diversity in choice.
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