Future of Signature Moves (in PVE)

Do you think Signature Moves reached rock bottom yet? (Since both Mist Ball and Luster Purge are trashed in PVE)
Signature moves were off with a good start with Psystrike, Aeroblast, V-create and co. all outshine their respective counter-parts, then followed by a downturn since Sacred Fire.
Will Niantic trash other signature moves (Dragon Ascent; Roar of Time; etc) on PVE just to boost PVP?

Sacred Sword is excellent as a move itself, but Terrakion needs a fighting fast move to really make use of it except for targets weak to both rock and fighting. Aeroblast isn’t as good as Psystrike but still great, and Sacred Fire at least is better than Fire Blast. The real tragedy is Mist Ball/Luster Purge, being even inferior to Psychic.
If Niantic still has some logic in handling signature moves in PvE, I guess, they tend to make single-bar moves on bulkier mon (Lugia, Ho-Oh, Eon Duo), and multi-bar moves on less bulky mon (Mewtwo, Justice Trio). I don’t consider mythical mon like Jirachi and Victini since they’re less relevant owing to the number limitation.
If that is the case, Kyogre and Groudon’s signature moves will probably be 1-bar and not as good as Aeroblast, so won’t be very attractive. Same goes for Giratina, Reshiram, Zekrom, Yveltal etc. Rayquaza may have Dragon Ascent as 2-bar since it’s relatively glassy, and it already has the 1-bar Hurricane as another flying exclusive move. Regarding Dialga and Palkia, as Roar of Time and Spacial Rend are both dragon type but have very different parameters in MSG (contrary to Mist Ball/Luster Purge), I expect Roar of Time being 1-bar while Spacial Rend being 2-bar, for the user’s bulk and resistances favouring Dialga’s side.
Above all, with Niantic’s talent in disappointing players, Dragon Ascent and Spacial Rend (or add Wildbolt Storm as well) are the only future signature moves I still care about. As long as they’re handled well, I can accept any bad setting on other moves.

Yes, I’d say we’re at rock bottom. Problem is Niantic have some serious (metaphorical) heavy machinery and are more than capable of taking things much further downhill.