Considering that it would be way too strong or too weak it’s not really a good way. Presumably at one point we would get something like that anyway and considering the fact that all the other sups have 1-2 things more to do than Mercy only increases the idea for an interactive skill like that in her kit.
Another Team utility abiltiy would just again be something which would end in the “No skill, blame Mercy” toxicity, not to forget the fact that something like that would be very unbalanced.
Just if you want to take a look at my thought process during the development of the Pacify idea:
That’s the raw pattern how an E ability for Mercy should be. I was thinking about an E abbility for her now since 1 year. No idea so far was really impressive or visualizable.
Pacify was the only thing which more or less created a picture, which can work, instantly after that raw ability idea was worked out. but any way.
I don’t see it as “broken in 1v1, useless in team fights”. It has a very specific in which it is very good (depending on the players skill) or just bad if it gets countered.
The only issue it has right now is the 60 or 50 HP/s with it. Other than that, nothing really bad came up so far.
Also…
I don’t know where read that Pacify slows Mercy’s movement. But the suggestion in the OP has no slow downs at all. only cast times.