Hero pools in various other games are often used in order to ban unpopular or unbalanced heroes from being played in a game. Overwatch was no exception, with the Overwatch Hero Pool that was added to the game’s competitive mode. Blizzard, however, is now removing the pool from the mode.
The reason behind it is apparently player complaints because instead of actual players having a choice of what heroes were banned in competitive play, Blizzard made the decisions. This resulted in both casual and competitive players being angry, and so Blizzard has retired the system.
The way that hero pools worked in Overwatch was that Blizzard would make a rotating ban of various heroes that could not be used in multiplayer. According to Blizzard, this was implemented to keep the meta fresh. However, with the help of the Experimental Cards system and more hero balance updates, the Overwatch Hero Pool banning system is no longer needed.
That doesn’t mean that the system will be disappearing from the actual Overwatch League, however. Instead, the system will now be banning heroes for two weeks at a time, except during tournaments and the week leading up to them. This has its own various problems.
Professinal Overwatch players often specialize with one particular character in the game, and considering how much practice goes into making an effective team, losing the ability to play your character for two weeks can make you rusty.
This has resulted in many teams apparently just being lost during tournament matches, but hopefully the changes to the Overwatch hero pool mechanic in that part of the game’s multiplayer will at least be able to help the teams be able to adjust more.
Otherwise, all players can really do is try to branch out their heroes and try to become competent with all of them, even if you aren’t able to master a single hero because of the banning.