So I’m not a Mercy Main but while thinking it over I realized that Mercy’s Valkyrie is currently still completely balanced around Mercy’s Old Resurrect.
At the time of the rework, Mercy had instant Rez. Valkyrie refreshed Rez and made Rez’s cooldown 10 seconds for its duration. Valkyrie lasted 20 seconds.
Now obviously this is overpowered because this makes Mercy capable of getting 3 rezzes in 1 team fight but it also explains why Valkyrie does so little healing compared to other support Ults. If it did something like 120 hps, it would make winning the team fight impossible for the enemy team.
Blizzard has said that they wanted to not have Mercys hide and let the team die so they gave her an ultimate that lets her be in the fight without actually having to be directly in the fight because she can just hover over the battlefield.
They also made it so that she doesn’t die to focus fire while hovering because then it would be useless so she has active regeneration and faster speed.
It also increased her combat capabilities in case players wanted to play that way.
Of course there was always a reason to come back to the ground because Rez was instant back then.
Nowadays, Rez takes 1.75 seconds which makes it impractical to use in the middle of combat. Valkyrie no longer refreshes Rez either and lasts 15 seconds.
While using Valkyrie today, there are currently few optimal situations where it is beneficial to come back directly into the fight because they’ll get you instantly killed if you’re losing the fight.
Also, unlike Moira’s ultimate, you can’t stop a Death Blossom or similar damage numbers with chain healing. (Death Blossom does 170 dps for 3 seconds. Moira’s ultimate does 140 hps.)
So…yeah. They should probably give Mercy something that she can actually do in Valkyrie.