He dodged a bullet there then lol. I dunno I just don't like Scyther - or Scizor - so I'm thankful that Go caught it because that means that we probably won't see Scyther that often.
For me its not necessarily dislike, but it's a either one or the other situation because I feel certain Pokemon just work better as rivals to one another then Ash having both. Like Pidgeot vs. Fearow.
While Scyther might be ok and be a good Bug/Flying replacement for Butterfree.
Scizor has the problem of being something of a rival bug to Heracross. They fought in Johto and it was a good fight for that period. And well sure you could say "Well Ash's Scyther doesn't have to evolve" and maybe that'd be a solution, but I feel I need to take the entire evolution line into account so I can't just ignore it.
Speaking of Kanto Ash now has 12-16 Kanto captures (counting the Tauros as 1) depending on the source. Pikachu, Butterfree (Released), Pidgeot (Released), Bulbasaur, Charizard, Squirtle, Kingler, Raticate (Traded for then back), Primeape, Muk, Tauros, Mr. Mime, Lapras (Released), Snorlax, Beedrill (gave away), Seaking (wasn't allowed to keep it).
Of these I would not count Raticate, Beedrill, and Seaking. On a technical level yes, but in spirit these 3 are not Ash's Pokemon.
That said I'm honestly annoyed Haunter was excluded if they're willing to count Raticate and Seaking. He got Ash his Marsh Badge for crying out loud! The Japanese title for his debut episode even was "Capture at Pokemon Tower". If Ash has to get anything else from Kanto the Gastly line would be my top pick. Everything else? Cross-region evolutions or regional variants.