Blizzard has been nerfing, tweaking, balancing, altering, and changing Mercy since before Overwatch entered into beta, and have been performing the aforementioned actions long after the game released. Well, the latest changes have been rolled out through the public test realm, proving that the developers still can't figure out how to fix Mercy.
The news comes courtesy of a changelog that was rolled out over on the official Battle.net forums via Blizzard Entertainment's Geoff Goodman. The changelog reveals that the latest PTR rollout will affect Mercy in a big way, again. This time the developers modified her Valkyrie skill, making Resurrect no longer instant, and there is no longer a bonus charge of Resurrect.
Additionally, Mercy has been nerfed even more given that the speed boost for Guardian Angel was decreased by 50% and the duration of the Valkyrie ability has been reduced down to 15 seconds compared to when it used to be 20 seconds.
So what were the reasons behind the changes? Well, according to Goodman, it was all about giving Mercy's enemies more counter-play opportunities against her. Previously, the Valkyrie skill allowed Mercy to "mitigate the impact" of other changes made to balance her out, so the team decided to further nerf her abilities to make the popular Overwatch hero more manageable.
Goodman further explains that the team decided to reduce Mercy's mobility provided through Guardian Angel by reducing its duration and reducing the power of the ability while Valkyrie is active. Essentially it's to de-power the very powerful healing character.
As is usual with most major character changes, the community was highly engaged with the changes. Many users made it known that they did not like that Mercy was debuffed, given that she happened to be their favorite Overwatch character. Others felt that while Mercy did need a debuff, making it where she lost a second charge and adding more cast time has made her -- in the words of user LiamHD -- "unsatisfying to use".
One thing worth noting is that Mercy wasn't the only one who had some changes made. Junkrat was also affected by the update, but the only thing that was changed for Junkrat in PTR was that his concussion mine deals less damage to those who are further away from the center of the blast.
As pointed out in the comment section, most people felt Junkrat's modification was barely worth anything, but that Mercy received too much attention... and the wrong kind of attention, even though Mercy has been getting buffed and debuffed for ages now.
There are two sides to the coin, however. On one side, Blizzard can gauge the feedback from the community who aren't fond of the new changes made to Mercy -- changes that have been ongoing and continual since the game's beta. On the other side, this is still the Public Test Realm update for Overwatch, so it's possible that these changes could be rolled back or not make it into the final public build at all. It's also likely Blizzard may reconvene on the issue to find a balance somewhere that makes Mercy both fun to play and a little less overpowered on the battlefield.