Not in public setting, but it was trash even there. It’s my favourite kind of winning, since those 25% extra health quickly stack up, when you have 15 teammates.
High HPS means, that you get to start applying overheal sooner. Either way Mercy won’t get overheal in OW2, as it would be instantly called “too strong”. Even while “too strong” abilities are mandatory in your average game, where players just run forward and get gunned down.
Mercy isn’t outdated, she is kept down on purpose.