I just hope some of the M8 battles involve bringing reserves back. It doesn't feel like the pinnacle of all Ash's journeys if you don't bring the Pokemon that helped him reach this level.
A victory vs Drasna means every pokémon of Ash had their time to power up and shine:
Lucario: Bea, mega evolution and new move
Pikachu: Volkner, return of Z-move
Gengar: Marnie, gigantamax and new moves
Dragonite: Iris and new move
Dracovish and Sirfetch'd: Drasna and new moves
So while I still think it's unlikely, at least this opens up more space to possibly have reserves