Personally I think mercy is played as often as she is because of her damage boost. The other supports don’t really have a buff ability that isn’t an ult. That and her mobility is unmatched in support. I mean Lucio speed and wall ride sure but he’s often just doing his own thing.
I think adjusting/ reworking other supports and abilities could alleviate her pickrate but thats unlikely.
They said overbuff numbers are pretty accurate in that AMA no?