Alright.
A lot of people still seem to think Mercy 1.0 gameplay was only about “hide and rez” so I’m going to explain you how I see the game (and every other game aswell) because in my opinion it is so logical I can’t even imagine how to not understand this concept.
Let’s talk about resources.
Every skill represents a resource. Overwatch is about using the resource you have in order to force your oponent to run out of their own resources so that you can win a fight, and then, the match.
There are different types of resources:
In general case Free to use < Cooldown based < Ultimates in terms of power and value you can get from it.
The whole point is trying to use the least resource possible to get the best benefits from it. Starting from there, your objective is to trade some of your resources against your oponents resources. Using a single resource to cancel what your ennemy does with 2 or more resources is a trade in your favor (actually it is a bit more complex because every resource does not have the same value, but we can still say using a not very powerful resource to counter a much powerful resource is a trade in your favor).
People are saying: “it is powerful/broken to deliberately let your teammates die then resurect them” which we can rephrase into “it is a trade in your favor to not use your hero’s free to use resources before using your ultimate resource”
Let’s examinate the 2 possibilities (sorry this might be long)
1. You are not using your free to use resources before using your ultimate
If you do not use your “free to use” resources (which is an unlimited source of resource) then you are not forcing your ennemy to use theirs to counter it.
Simple example: You are not healing Reinhardt who is fighting in a 1v1 against Winston. Assuming Winston is only left-clicking, Reinhardt suffers 60 dps.
2. You are using your free to use resources before using your ultimate
You are spending your unlimited type of resource which is forcing the ennemy to use more resources to get an advantage over you.
Again, same example: Reinhardt vs Winston.
Winson’s left click is completly canceled by your healing, meaning he will 100% loose this fight if he doesn’t use any other resource. => You are forcing him to use something if he doesn’t want to die.
Then, refusing to heal your teammates before resurecting is a bad way to play.
It will be easier for your oponents to win the fight than if you were healing meaning they might not be forced to use their ultimates. Ultimates they have saved as a resource to counter your ultimate resource when you will use it.
Here’s a quick example of a teamfight thinking about resources:
Both teams have charged up all their ultimates. The fight is going to engage.
Assuming free to use resources from team A perfectly counters free to use resources from team B. Same for cooldown based.
1. Mercy from team A decides to go for hiding and wait until her team dies.
Team A is left 5v6 and their free to use + cooldown based resources no longer perfectly cancels the ones of team B.
The fight ends up by team A loosing the fight after using 4 ult vs team B using only 3 ults (noone died from team B).
Mercy comes and uses her ultimate to reset a new fight and now team A has 1 ultimate left, against 3 for team B. Now free to use + cooldown based resources are equal for both teams.
Who wins ?
2. Mercy from team A decides to take part to the fight.
As free to use resources + cooldown based perfectly cancels itselves, the outcome of the fight will depend on how each team uses their ultimates.
Victory is possible for both teams.
People saying “hide and rez” is broken are basically saying team B uses 6 ults to win the fight against only 5 people. But in fact their regular abilities are enough to get an advantage over team A. And when team A uses their ults to try to change the issue of the fight in their favor, team B only has to use as much ultimates as team A did to counter it.
[Sorry for the huge post, I wanted to be as clear as possible so I detailled everything.]
TL; DR
“Hide and rez” strategy is only viable against poor teamworking, as mentionned a billion times.