I would love this. It would be impossible (or atleast boring) to have every Pokemon be equally viable, but they could give each Pokemon a niche.

They should also nerf the top 20% used non-legendary Pokemon as long as they aren't counter or popularity picks. (Unaware Quagsire or Charizard have been highly used, but not overwhelming powerful.) I would like to see them go back to their original system of Powerful Pokemon have a more narrow movepool, while versatile Pokemon have less attack power.

I think buffing signature moves when used by their matching Pokemon. (To not buff Smeargle)

Crush Claw (Zangoose, Sandslash) could have priority, or lower defense before damage is applied.

Octozooka (Octillary) should be slightly stronger than surf along with it's accuracy lowering effect.

Skullbash (Blastoise/Avalugg) increase defense by two-three stages and reduce overall damage recieved by half while charging.

This could be a really good way to pinpoint buff Pokemon without accidentally buffing already strong Pokemon.