I don’t know ; I’ve saved more people with Moira right click in S9 than any other season.
Her purple orb is beyond useless now if its not to secure a kill. As it can’t kill anything by its own, its just giving enemy ultimate points.
Ana can also save people by taking out enemies dueling afar from her. Yet its hard to do since ally would usually catch up the shot.
Her Grenade is now clearly a defensive tool whereas it was good only on offense before.
To get back about Mercy, I guess she depends on her mates.
To figure out if she could still healbotting, maybe watching how GM plays her right now might help but imo, at lower ranks, I’d think she’s better using her gun as long as her supported mate ain’t in critical state.