This is a copy of something I posted in the Overwatch Feedback Forum regarding the late-2017 changes to the healing character Mercy.
Caveats in advance: I prefer old Mercy, am used to current Mercy, and what I am going to suggest is something nobody wants, which is yet another massive overhaul to Mercy. I would also accept old Mercy again.
In addition to just not really liking the New Mercy mechanically, it doesn't fit with her character, especially Valkyrie. Single res in general, but specifically during Valkyrie, is basically just encouraging the doctor to sacrifice her life for a chance at one patient. A heroic doctor might sacrifice her life for a chance to save several people at once, but a heroic doctor will not hover in midair with a giant target painted on her in order to get a better angle on maybe getting a chance to save one more patient, maybe.
I have been trying to think of a good metaphor to describe the difference between old and new Mercy Res and was thinking of it as healing as weapons, like old Mercy Res was a "healing nuke"--but I don't think that's right anymore. Res is not really a healing move, it is more troop deployment; a heal would bring you back starting from zero health, instead you get a fresh hero that just so happens to be standing where the last one fell. This is important to the enemy, because the difference between a wounded tank and a full-health tank is a whole lot of hit points.
But for a "troop deployment hero" Mercy is super-limited. Symmetra can choose a place and defend it. D.Va gets a new suit deployed to her after her baby Ultimate recharges, which she can deploy anywhere and anywhen after that. Mercy is currently limited to one hero, at the place where they fell, within a few seconds (what is it, 15? 20?) of when they fell.
Valkyrie doesn't fit her character well and doesn't do a lot to help with the problems inherent to Res. The heal chain is also kind of weird; a doctor should have personal relationships but heal chain is kind of... healing people by accident because they are standing near the person you are trying to heal. Powering up several people at once is similarly... not-medic-y.
So once I thought about Res as troop insertion I started thinking about what abilities you can give her that synergize with that mechanic, and there are basically three: massive area of effect (classic ult Res), bring dead bodies to you, or teleport.
My suggestion, below, will be the last of those three, but it is worth taking a moment to properly scratch "bring bodies to you" off the list. When you resurrect players where they fell, they will know exactly where they are immediately, and that's important to help quell that moment of panic if you are resurrected in the middle of a firefight. The idea of fetching bodies means they are less likely to be resurrected in a firefight, but it can also lead to a lot of confusion, and it has some of the same problems as the teleport I'm going to suggest below, namely, you will be able to resurrect people in places they normally can't reach, like putting Symmetra on a small high ledge where she can drop a teleporter for even more havoc. Also, moving bodies to you seems like it could get pretty glitchy, with a chance of resurrecting people in places they would never naturally be, like in walls or underneath the map.
Again, with the caveat that I understand nobody really wants another Mercy rework, let me suggest an alternative Ultimate for Mercy: double down on the "Resurrection is troop insertion" metaphor and give Mercy a teleport ultimate, similar to Reaper or Doomfist. However, unlike those, I think it would be most interesting for this ability to allow Mercy to bring others along with her.
The idea in my head is this: Mercy taps the activation key to start the move, and a glowing sprite character appears above or in front of her, under her control. This sprite should be highly visible and can be killed, disarming the ability and wasting the ultimate. The sprite might control like a normal character, or like Valkyrie Mercy, or like Junkrat's Wheel, or like Doomfist's Meteor Strike; it'd take testing to figure out which. Presumably, the sprite would have either a hard distance limit, or a time limit, in addition to the other restrictions.
At the same time, for teammates, a circle shows up on the ground around her.
From Mercy's point of view, a hologram on the ground under the sprite shows where the teleport will end up, and also show everything within the circle around her exactly where it will be if she teleports at that instant. At this point, Mercy moves the sprite to where she wishes to teleport, and presses the activation button again; both the source and destination locations are filled with light, and everything in the first location is moved to the second. (Alternately, hold the activation button; a tap moves only Mercy, but a longer hold moves more and more of the circle with her. A full-circle teleport might take a few seconds, but if you are moving only one additional person, you could shave off some time.)
This ability has all the consequences that an ultimate should have. It is dangerous when misused, prone to getting her in trouble, harmonizes with her role as healer and resurrector, useful for covering larger distances, requires teamwork, gives away her intentions quickly but ambiguously, and most importantly, it allows the player to make clever strategic decisions. An unwise teleport could lead everyone involved into a deathtrap, and the earlier it is detected, the more likely it will be countered; however, a clever use of the ability could drop several heroes (maybe not an entire team?) on the enemy's flank, or position heroes in places that they normally cannot reach. It's also possible that an enemy (say Sombra) could sneak into the circle and be teleported with you. It's an interesting thought.
I understand that there is a (unspoken?) taboo about character abilities that give characters without high maneuverability (eg not Pharah) access to inaccessible places, and this might violate that taboo. That is most important in a few edge cases, like Torbjorn, Symmetra, and Bastion. All of these three characters were given strong abilities, and as a trade, they all are limited to normal movement. They cannot get to inaccessible places, and so cannot deploy assets in inaccessible places. A teleporter will always be in a place that all enemy characters could theoretically reach, on foot, given enough time, and so will every Bastion and every turret. These limitations are most likely correct and probably shouldn't be changed, although it would make the game VERY interesting.
To make sure of that, you could introduce a number of restrictions that would minimize, and/or completely remove the potential for things like "Symmetra on a shelf"; for instance, simply make those surfaces not be a viable surface for Mercy to teleport to, or prevent the Mercy sprite from moving out of the ground plane. Similarly, the ability may stipulate that characters and equipment will only teleport if they would all land on the same solid surface, and so while you might get one or two characters on a thin ledge, you cannot use that ledge to drop a whole team into the middle of an enemy assault.
What is most important to me about this troop transport idea is that it is more in keeping with the idea of a medic than Valkyrie is. Yes, it will mostly be used for attacking, but it will be used to get a lot of her comrades where they are going [u]safely[/u], and that is in keeping with her as a medic. It allows the team to advance behind the cover of, say, a Reinhardt shield, instead of funneling into a grinder. It keeps the team together and allows her to get to people stranded behind enemy lines without committing bloody suicide.
And it certainly is more medic-y than boosting a bunch of people's weapons all at once, while flying around in the sky on fire like a bloody phoenix.