These changes would have just made the behavior of Mass Resurrect worse. I see this having been recommended all the time, but really think about it. The reason they added invuln to Mercy was because of how frequently she died using it – no other support ultimate (at the time) was so counterintuitive that it was consistently leaving the support dead, which was highly ironic since the whole point was to restart a team fight. Invuln put it up to speed with other ultimates and enabled Mercy to have more control over her ult, rather than reserving it for a five-man wipe to ensure it would be a successful play.
LOS checks would have done nothing but make the ultimate feel wonky and unfair. Mercy already had the silly worry about positioning herself to get all the resses she wanted, adding LOS checks would mean a single trash can could prevent a res she wanted. It would not have made the ability feel any better, and it would have only encouraged the five-man res problem by having teammates purposefully die close together and without LOS breaks. This is why Blizzard didn’t go through with these changes, because the core problem was never being addressed, and at the same time, it was just going to make Mercy a worse hero than she already was.
Mercy was both underpowered and plagued with a problematic kit. Both issues needed addressing, hence why Mass Res was given the boot and why Mercy’s kit was made more dynamic. A new ability to use that gives her impact in the mid-fight, and an adaptable ultimate that lets Mercy have greater independence. Her reworked kit has significantly less problems to have to balance around, while also putting an iconic ability in a much healthier place and expanding what any individual Mercy can do in a game.
To the OP: the rework was a huge success. Mass Resurrect was horrible not just for the game itself, but especially for Mercy, whose kit was burdened by the potential her ultimate carried. Her base kit had to be weak in order to allow such a massive play like a five-man res to exist. This rework gives her more to do, more to think about, overall keeps her far more engaged in the game, and without any problematic aspects towards the greater health of the game. She’s usable, she’s fun, the rework was a success.
I don’t know why listing all the nerfs is considered an argument. Like, yeah, you are right, Mercy’s initial rework was overpowered and literally no one denies that. She had to be nerfed because she was blatantly too strong. Literally every nerf has been warranted to keep her a healthy and fair character. So I don’t even consider that, like, a “flaw” of the rework. A rough patch for Overwatch to cross, but the problems caused by her rework were fixed. It’s about what I can expect when any character undergoes significant reworking, and well worth the wait when it puts Mercy in such a fine spot.
I’m sorry that you don’t see the value in Valkyrie and Resurrect, but it’s absolutely there and makes impacts in the game. My head will spin right off my neck if I get any deeper into this, I shouldn’t really have to explain the power Valkyrie provides and how Resurrect is an engaging, thrilling ability with the potential to make big turnarounds or otherwise enforce a victory. Not seeing the value of these abilities or why they’re designed the way they are is… really just telling me that you don’t understand Mercy as she is, and aren’t willing to learn. If you really want a deeper argument to read, just coast through my post history, you’ll certainly see somewhere I’ve explained the fun and value in these abilities.
Mercy’s honestly in a great state to be playing, especially if you’re not in some higher rank where metas truly dominate. Anyone at Plat or lower, trust me, you’re not losing because Mercy is “just that bad,” you’re losing for the same reasons you lose any game. And if you’re just not a fan of how Mercy plays, I strongly encourage you to pick up different heroes and accept that Mercy isn’t for you and she isn’t likely to be twisted into what you want.
