This demonstrates a lack of understanding of what made Mercy good.
Let me reiterate here:
Valkyrie is not a game changing ultimate. Examples of game changing ultimates are those that you would choose a hero just to have their ultimate.
Zarya’s ultimate is one such example. Her ultimate is so good at getting a team kill that sometimes people will switch to Zarya even if she doesn’t work with her team’s composition or against the enemy composition, just because it’s worth waiting for a graviton and using it to take point B on 2CP.
Genji’s ultimate is another such example. Sometimes Genji is a terrible choice against the enemy’s comp, but just spamming shurikens at long range to get an ult is sometimes worth it, because his ultimate wins games.
Zenyatta and Lucio are examples of support ultimates which are worth taking the hero just to use. They are the only defensive ultimates, used to counteract the other game changing ultimates such as Graviton or Dragonblade. If the enemy keeps winning fights with those ultimates, then somebody might switch to Zenyatta or Lucio, even if they are not particularly useful in your game, just to use the ultimate.
Valkyrie is not a game changing ultimate. Nobody has ever said “please go Mercy because we need a Valkyire”.
I’m not saying it’s a bad ult. It’s a great ult and it wins fights, it’s just not a game changer.
So buffing Mercy’s ultimate will not increase her viability. For it to be worth taking Mercy, she needs to be worth taking outside of her ultimate.
The only things Mercy brings to the table are:
- Healing
- Damage boosting
- Survivability/mobility
- Resurrect
They nerfed the first one, which makes her no longer worth taking over Ana or Moira.
The second one isn’t worth having if Mercy cannot keep people alive - you can’t damage boost dead people. For it to be worth it, they would have to increase the amount it increases damage, and they tried that once before and it resulted in oppressive gameplay (too high damage McCree etc).
The third one is pointless without good heals. It doesn’t matter if Mercy can survive/escape with GA and regenerate her health, if her own team dies. Her mobility and survivability is based on her own team, so effectively, it has been nerfed.
The last one would be a terrible idea to buff. Resurrect used to be more powerful and it led to regressive gameplay and made Mercy a must pick because all fights were 7v6. So they cannot buff that again.
So what are we left with? Mercy needs better healing. It’s her raison d’être and nerfing it was a mistake. It at least needs partially un-nerfing, e.g. 55 health per second.