This comes with the underlying assumption that it's getting to +2 when deterring set up of any kind is entirely mandatory on every mon you run in this meta.
Mega Scizor is only coming in on Mega Pinsir in one of two ways.
-Manual switch, leading to the scenario I described as a possibility.
-Something died to let Mega Scizor in, presumably by threatening Mega Pinsir so badly Mega Pinsir couldn't risk the Swords Dance.
The latter is unacceptable. Even taking into account that Mega Pinsir is weak to Stealth Rock, it only ensures that Mega Scizor can stop an uncontrolled sweep, not that it acts as a reliable check or counter to Mega Pinsir.
The former is also unacceptable. It means Mega Pinsir can win a prediction or come in on something that can't do anything worth commentary to it, and your Mega Scizor is invalidated as a check/counter, instantly.
That core can't actually be counted on to check Mega Pinsir. Pressure it to make the right decisions -Swords Dance is wrong if you switch in Aurorus but Close Combat is wrong if you switch in Mega Scizor and either way it has to run right now- sure, but it, by itself, can use prediction to kill both of them if they try to do anything other than stop its rampage after a KO. That's shaky, even defining them as checks.
Sorry, but Ghost types are only checks to Diggersby. They don't switch into it.
252+ Atk Life Orb Huge Power Diggersby Earthquake vs. 252 HP / 252+ Def Mega Sableye: 169-200 (55.5 - 65.7%)
252+ Atk Life Orb Huge Power Diggersby Earthquake vs. 252 HP / 252+ Def Sableye: 238-281 (78.2 - 92.4%) -- 31.3% chance to OHKO after Stealth Rock
252+ Atk Life Orb Huge Power Diggersby Fire Punch vs. 0 HP / 0 Def Gengar: 208-246 (80.3 - 94.9%) -- 50% chance to OHKO after Stealth Rock
There is also no Steel type that switches into Diggersby I'm afraid, as Bronzong either lacks Heatproof or Levitate.
252+ Atk Life Orb Huge Power Diggersby Fire Punch vs. 252 HP / 252+ Def Skarmory: 159-187 (47.6 - 55.9%) -- guaranteed 2HKO after Stealth Rock and Leftovers recovery
252+ Atk Life Orb Huge Power Diggersby Earthquake vs. 252 HP / 252+ Def Filter Mega Aggron: 160-189 (46.5 - 54.9%) -- 98.4% chance to 2HKO after Stealth Rock
Since Ghost and Steel as normal resists are out of the question, the only switch ins I can come up with are Mega Slowbro and Aerodactyl.
I never said Ghosts were counters, my point was simply that Diggersby is
easier to check than Mega Pinsir. You've got options that just aren't available against Mega Pinsir. Zapdos is the only thing off the top of my head that is the reverse: a workable check/counter to Mega Pinsir that Diggersby laughs at.
I wouldn't cry if Diggersby was kicked out the meta by any stretch of the imagination, but if it's broken it's still
less broken than Mega Pinsir.
Though I don't see why you're mentioning Fire Punch. I can't imagine a Diggersby build that would bother, and Knock Off kills Bronzong regardless of Ability, while Skarmory dies much more reliably to Wild Charge -no need for Stealth Rock to ensure the kill.
Also Aerodactyl dies instantly to Wild Charge. And Banded Diggersby has a 99.6% chance of 2HKOing Mega Slowbro with Wild Charge, too. (I hate Banded Diggersby) Assuming it was Mega Evolved for both hits and there were no hazards, by the way.
If Diggersby isn't Banded and doesn't Swords Dance, Cofagrigus is an amusing check. Even if it's either of those, it has to use Knock Off, not Earthquake, to get the KO before being Will O Wisped, so Cofagrigus is a pretty reliable way to force Diggersby out one time, and you can give Cofagrigus reliable recovery!
