Over the past couple of months, Overwatch players may have noticed that the game's most prolific healer, Mercy, has been enjoying a dominating pickrate in virtually every single match in both normal gameplay and in the Overwatch League. As it turns out, being able to instantly revive two teammates while simultaneously keeping the other three members of the team alive from most normal sources of damage for 20 seconds is far more annoying and exponentially more powerful than being able to undo the occasional Team Kill, so Blizzard took action and decided to nerf Mercy...again.
As of the latest Overwatch balancing update, Mercy's Ultimate ability, Valkyrie, only lasts for 15 seconds (down from 20 seconds) and the speed boost that it provides to Guardian Angel has been reduced by 50%. Furthermore, Valkyrie will no longer grant an extra Resurrect charge, nor will it negate Resurrect's casting time. Junkrat also received a relatively minor nerf in that his Concussion Mine will have damage falloff; Mines must now detonate closer to a target to deal the full 120 points of damage.
It should be noted that while the Valkyrie changes were available on Overwatch's PTR server for the past month or so, reception to the update may still be a bit mixed. On the one hand, it does release Mercy's stranglehold on the game. However, some people have claimed that the nerf goes too far as Resurrect's significant casting time (which leaves Mercy quite vulnerable) makes it excessively dangerous to use during the now shortened duration of Valkyrie. Curiously enough, despite such feedback from the PTR, Blizzard evidently went ahead and implemented the nerfs in their entirety.