1. Why not replace mercy’s res with an instant res (which leaves a character as a ghost, in which once their death timer of 20 sec’s is over they actually respawn at spawn) maybe even decrease the dmg a character deals n slows them.
OR
2. Make mercy’s res basically a mcree ult (LoS, Line of Sight)
OR
**3.**Allow mercy to put a marker on a character which (if they die) will resurrect them (whether there be a delay/ instant res. I would also like a small period of invulerability, but thats unlikely)
On the topic of mercy’s heals:
What if we changed it so that mercy has the ability to affect the heal output?
Why you ask?
Instead of nerfing mercy’s current heal rate, why not change it so that her healing passive is either removed or changed!
My idea is that say you can output +60/s, mercy gets 0/s of healing passively ALWAYS. (Make the output lowest to +40/s)
But per -5 less healing per second she gets a passive heal of +3 (Therefore making her max passive heal +12/s (-8/s less than her “Out of Combat” heal.)
Alternate to Passive:
Basically the same idea above but depending on mercy’s heal rate she gains a +{number}% dmg reduction.
Example: +40/s = 20% dmg reduction to mercy (I’m just throwing numbers out there atm tbh) Maybe have it so that per less -5/s healing she gets 5% dmg reduction? or make it like 2 or 3% per -5/s
If not that:
Give mercy an overcharge ability to use on her healing (I would say dmg boost… but uh, that seems abit too much)
Say mercy’s heal is +50/s when she activates overcharge she can output +60/s for
maybe 3 seconds and has to wait 5 seconds to use it again
(Or you could go the resource route where you have to heal a certain amount or dmg a certain amount, which technically the dmg would entice mercy players to use dmg boost more often. but once again, seems like a lil bit much… as it would bring back the full on pharah/mercy meta)
PLEASE REMEMEBER:
These are all purely ideas, so feel free to critique but don’t just blatantly smoosh my ideas into the ground. 
P.s Yes, my formatting is HORRID… ;c