Update 03/03/2018
Adding in statistical analysis of the last round of OWL. TLDR? Mercy’s who did not use their ultimate won (slightly) more fights than mercies who did.
This heavily supports the “Valk has no impact on fights” Arguement that this post makes.
https**://www.reddit.com/r/Competitiveoverwatch/comments/80gpi7/five_amazing_stats_from_owl_stage_2_week_1/
There was a very strange trend taking place last week with respect to Mercy’s Valkyrie. Mercy took part in 282 team fights and finished Week 1 with the 6th highest overall win-rate of any hero – not bad, right? However, she was the only hero (excluding Orisa who was not used in enough team fights) to post a higher team fight win % in fights where she didn’t use Valkyrie. Mercy won 49.30% of such fights compared to winning just 49.25% of those when Valkyrie was active. Even more odd, in fights where only one Mercy used Valkryie but both teams used the same number of ults, the Mercy team won just 38.46% of fights (Lucio, by comparison, won 53.19% of these types of fights). Even in fights where the Mercy team uses Valkyrie plus more ults than their opponents, they are still winning just 60% of such fights (3rd worst of any hero last week) whereas Lucio was at 72.73%.
Original post below
Hey guys,
So seeing as we still have people who seem to think Mercy is “Ok” (How?) I decided to break this down with some Math…
Mercy can EITHER damage boost OR heal. Lets see what other supports can do.
The numbers:
Damage boost Chain: 30%
- Comparable to Zen’s Discord orb, which is also 30% with fewer restrictions (players grouping up, etc) - Which is incidently an ‘e’ ability with no cooldown.
- Orisa’s ultimate, by comparison, is a 50% increase in damage, and she can still drop a shield and dps and orb people. And if the orb is destroyed thats ok, its not the same as a Mercy dying…
Healing Chain: 60hp/s
- Moira: 150 HP/s – 2.33x more – also 70 dps against enemies at the same time
- Zen: 300HP/s – 5x more. – Discord orb stays on 30% damage boost at the same time
- Lucio: 500hp instantly – Amp it up Heal/speed AND DPS/Boops at the same time
- Ana: 50% damage resist over 8 seconds and can still heal grenade sleep dart and heal other players all while the nano is going. And if Ana dies immediately after the Nano, thats ok, its still in play.
Valkyrie offers the following:
Chaining Heal
Chain Damage Boost
Flight
(Resurrect intentionally omitted, as this ability has nothing to do with Valk anymore, and is more of a liability in Valk than anything.)
Chain healing
Mercy heals 60 health per second with her healing beam. Now don’t get me wrong, chain healing is nice, but its not ultimate worthy. A competent team is not 6 people fighting 5 people. Its 6 people fighting 1-2 people. Chain healing does nothing against a smart team who knows how to focus damage, and 60 HPS is really not much. Thats enough to counter winston and maybe moira? But any other dps player is outdoing that. When the enemy is focusing, chain heal is pointless. Might as well not ult…
All other support characters get better healing potential than Mercy in her ultimate, and they can do other things while their heals play out. Mercy is stuck holding left click and nothing else. Meanwhile, he target is focused and killed.
Chain damage boost
Lots of people seem to use this as the argument for Mercy being “fine”. “She can use it to initiate a fight!” Damage boost grants a 30% increase in damage. Know what else does that? Zen’s discord orb. So lets compare the two.
Valkyrie damage boost:
Ultimate ability.
Choose between heal or damage boost (not both).
Chain ability - requires teammates to be near each other. (Not useful for flankers)
Discord Orb
‘E’ Ability with no cooldown
Can heal AND DPS while your discord is on an enemy.
Targetted Ability - Does not require teammates to be near each other (Useful for flankers and non-flankers)
So…in my opinion, discord is more powerful than valkyrie, and its an ability without a cooldown. What?!
Orisa’s ultimate, widely considered one of the weakest and least impactful in the game, is a whopping 50% damage boost (the same as Ana’s, except it affects a 25 meter radius rather than just 1 player), which is 66% more powerful than Mercy’s damage boost. Immediately after dropping it, she can put a shield in front of it to protect it from damage, and continue to shoot her enemies, use fortify, and use her orb abilities. Her ultimate is passive, and if the enemy tries to focus it down, it means they aren’t shooting your teammates, they are shooting a drum. A drum thats gonna expire soon anyway. Assuming it takes 5 seconds to kill that drum, thats 5 seconds of not being shot at by the enemy team for your teammates. I’ve seen junkrats burn a tire to take out that drum.
Compare this to Mercy, who can fly but has no shield, and can’t use any other abilities while chain damage boosting, and if she dies, now you’re short a healer.
Does damage boost stack with these two abiltiies? Yup! But most Mercy players will tell you chain damage boost is just a nice to have rather than a game changing ultimate style ability. Your priority, first and foremost, is to heal. Mercy almost always needs to be healing. Now and then, when the team is full HP, you can damage boost. But if you let someone die so you can damage boost the team, you’ve failed.
Flight
Yup, this is pretty cool. No complaints here. Some people seem to think this makes her invulnerable (it doesn’t). But it does increase her survivability. However, I guess the argument can be made that if her ultimate no longer really does a great job of keeping her team alive, why is she a priority target anymore? 
I’ve been in fights where I’m kind of ignored anymore, and the enemy just bursts down whoever I’m healing. Then we’re down a person or 2, and guess what? No res. So we lose. Theres nothing I can do to keep my teammate alive. Theres no ‘gittin gud’ option. Its I’m healing you, you’re taking more damage than I can heal, you die, game over.
Zen can pop his ult, and quickly heal the whole team. 300 health per second (5x what Mercy can do…) while maintaining discord on whoever he last put it on. So, you know, kind of like hes chain damage boosting and doing 5x chain heals at the same time?
Lucio can pop his ult, and quickly shield his whole team – 500hp instantly added to all teammates, which takes Mercy 8.33 seconds to accomplish. Meanwhile hes still amping it up with heals or speed boost, AND dpsing and booping people off the map.
Moira is doing 70 damage per second and 140 health per second to anyone she touches with her beam. Thats 2.33x the healing that mercy can dish out, AND shes doing damage to anyone who happens to be near the person shes healing.
Even Ana has a 50% damage reduction going on, which I would argue that when combines with a healing grenade will significantly prolong the life of an ally, not to mention give him a 50% damage boost.
Now I know what you’re thinking. All of these abilities are shorter than the 15 seconds that Valk lasts for. My response is, Valk could last for a minute for all it matters! This is a game of burst damage. Pushes at a high rank usually last for less than 15 seconds, and if 1 person is burst down during those 15 seconds, theres no winning that fight. Its now 5v6 and res is not an option during Valk.
There is no gittin gud. Game over man. Game over.