I found your arguments good except for these two arguments.
* Fire coverage is mandatory for Manectric, that's why he doesn't afraid of Grass type like Amoonguss or Celebi. Signal beam isn't bad to touch celebi yes, but for the rest ...
* I'm not agree at all, I'll explain myself:
If we look the stall teams in UU, for example the stall teams of pif: https://www.smogon.com/forums/threads/usum-sample-teams.3621217/page-4#post-8135067 :
In every team, there is 1 pokemon to take the uturn of the band and another to check the setup set. So Stall team doesn't fear Scizor at all.
Moreover, Scizor is viable in stall too, so Stall teams get a nerf with a Scizor ban, not a huge buff.
- Manectric becomes more annoying with no reason to run Fire-type coverage (ig yo hit Steelix?). Expect Toxic for stuff like Hippo or Signal Beam.
- Stall teams get a huge buff since a Toxic-immune sweeper with recovery just got banned. More leeway in building will make them a lot tougher to break.
* Fire coverage is mandatory for Manectric, that's why he doesn't afraid of Grass type like Amoonguss or Celebi. Signal beam isn't bad to touch celebi yes, but for the rest ...
* I'm not agree at all, I'll explain myself:
If we look the stall teams in UU, for example the stall teams of pif: https://www.smogon.com/forums/threads/usum-sample-teams.3621217/page-4#post-8135067 :
In every team, there is 1 pokemon to take the uturn of the band and another to check the setup set. So Stall team doesn't fear Scizor at all.
Moreover, Scizor is viable in stall too, so Stall teams get a nerf with a Scizor ban, not a huge buff.