Mercy would be extremely vulnerable during this moment, Lucio at least can amp heal/speed to endure/avoid damage during his cast time. Mercy would need some kind of resistance during this cast time, maybe uninterrupted healing?
This is actually a pretty good idea. I like the idea of being able to mass heal/damage boost temporarily. Just make it where she can’t fly during this time, or have uninterrupted healing. Also, the movement speed buff may be a little broken.
I like this direction of balancing Mercy, would love to test it on the PTR. +1