She’s not OP
She’s picked alot because even after 2 new supports introduced, she’s still the best Support at healing. Everybody else has really low heals and most of them aren’t really consistent. Not Mercy. All she has to do is attach that beam of hers onto you and you’re good to go.
We seriously need another support who can provide good consistent healing. That way we don’t have to rely on just Mercy for them good heals.