Overwatch McCree and Echo screenshot

[Update]: Blizzard is also looking into tweaking Moira and the support category as a whole.

Hero Pools (essentially hero bans) have been introduced to Overwatch in order to combat the stale meta and force teams to get creative when it comes to their strategies. However, while Hero Pools have been a decent success in the Overwatch League and in the higher echelons of Competitive Play, their impact in the lower ranks has been pretty negligible.

As such, the next update will be removing Hero Pools for Diamond rank and below, while maintaining it for Master and Grandmaster ranks, as well as the Overwatch League. Furthermore, in order to combat the recent trend of only popular but balanced heroes getting banned, the new Hero Pools will be based on Overwatch League data instead of high level Competitive Play data.

Blizzard will also be refining the algorithm that selects hero bans in order to avoid the dreaded 'ping-pong' problem where certain heroes like McCree just rotate in and out of being banned. The details behind this change haven't been revealed just yet, but I can only assume they'll make it so heroes that have recently been banned have a noticeably lower chance of getting picked anew.

The final thing worth mentioning is that the whole Hero Pools system was and still is under development. So if there end up being problems due to these changes, or if the overall community wants to see Hero Pools make a reappearance in Diamond and below, Blizzard is likely to shift things around once again.

You can read a little bit more about the upcoming changes over at the official website.