Hand Cannon fans have been unhappy with their weapon of choice's performance in PvE since Shadowkeep but it looks like Bungie will make them better along with two other archetypes.
Hand Cannons, Scout Rifles and Machine Guns rely on precision damage to be effective. In PvP, they still find their spots thanks to quick TTK, provided you score enough headshots at the optimal range but in PvE, this damage was nerfed back when Shadowkeep was released.
The woes of players who would like to use these weapons in PvE will apparently be answered. During the Firing Range podcast, Bungie noted that they are aware of these weapon types underperforming in PvE and stated that they will buff them in the future.
That said, they didn't specify when the buffs will come or what they will be like. On the other hand, it's highly possible the buffs will be about lowering the effects of the blanked nerf to precision damage in PvE as Bungie folks also noted they will never fully revert the precision damage changes from Shadowkeep.
As for the best guess on when the HC, Scout and MG buffs will arrive, fans are speculating it's will be at some point during Season 15, if not at the beginning of it. This means we will have to wait at least until August 24, 2021.
Therefore, if you've been hoarding Seventh Seraph Revolvers in the Vault, keep them a while longer - they will become highly useful if the damage gets on par with other weapons that produce Warmind Cells.