Since the implementation of Hero Pools in Overwatch League, the mechanic has been a hot topic among fans and players. Blizzard noticed this and gave an update regarding their treatment going forward on its official forums.
The first and largest change is that starting this weekend, Hero Pools eligibility will be based on hero usage rate from OWL games only. Previously, all high-levels of play were considered when determining who was eligible for a ban each week. Citing a wide variance in hero selection from the highest level of play and OWL games, Blizzard has made the decision to only use OWL matches to determine which heroes will be placed into the pool.
After the OWL season is finished, high-level Competitive Play matches will be used as the data to determine the banned heroes..
Blizzard also acknowledged the “ping-pong” of hero rotation that has been happening since the start of Hero Pools, and will make minor changes to the algorithm as a result. Fans should start to see much more varied Hero Pools. It is still unclear what changes will be made or when those changes will take effect.
Another large change that has no effect on the OWL is that Master and Grandmaster players will see the Hero Pool Mechanic. This change will take effect with the next patch, but Hero Pools will be temporarily disabled for all ranks on May 4 when the Hero Pool normally rotates.
As for what defines a Masters or Grandmasters match, the average SR must be at or above 3500 SR amongst all players on both teams. Even players who have not yet achieved their placements can be subject to a match that has Hero Pools enabled.
There has been no word on when the Hero Pools will be added back in but it will not be implemented with the 1.48 patch, which is set to release soon.