Firstly, welcome to the forums!
I agree with you in that Mercy lacks impact. I also am not a huge fan of the “Battle Mercy” persona surrounding Valkyrie. It comes off to me as them trying a bit too hard to make her “edgy”, in playing a role that she essentially isn’t naturally designed to be played in. I believe they can do a lot better with her design if they built upon her pacifist / advocate for peace characteristics. Especially so since it’s been so rooted in the character in general.
I also agree with you on the need to bring back Ressurect. I believe the ability was a great way to introduce an ultimate that was engaging, rewarding, and impactful, without having to “pop-off and shoot heads.” To me it simply fits her design, and I think a rework that includes a few tweaks to balance it out, as well as swapping the two so Valk is instead an E move, rather than her ultimate as it is currently, would really improve her current state.
I like the direction here. A few things I personally would suggest instead would be.
- A 55hp instead of 60hp base healing, just to attempt to hit that sweet spot in her dedicated healing and seeing if that would be enough, before going with a full revert of 60.
- Agree on damage boost. Though this may change, as the devs have stated that they will look into making it “feel better”.
- Instead of a cleanse by itself, which I think wouldn’t be strong enough on it’s own, I would perhaps suggest that it’s just incorporated into Valkyrie on a cooldown standard, as a sort of “passive” for that ability. I can settle with a 15-20 second cooldown on this as well since it’s incorporating Valkyrie along with it (albeit with some tweaks as well to balance it out).
- I think the Blaster damage is fine as is. I don’t see a need for an increase in DPS due to Ressurect making a return.
Besides those little nit-picks though, I certainly love the direction you went with this kit, and I would love to play it in-game. Nice one. 
~Sincerely Yours xoxo,
a Lover of True, Fair, and Fun Balance.
xavvypls 