Not Exactly Helping
It may not have been your conclusion, but it was my conclusion. It's hard to tell at this point what will and won't be a check or a counter because we don't know what the stats or ability of 25f will be. My "switch in" lists are all of the Pokemon that take at most neutral damage(M-Aggron being an exception) that are also somewhat bulky. I didn't have a specific stat threshold for bulkiness, just whatever I thought might work. So many of these won't end up actually being counters or even checks. I'm considering reordering them by their "bulkiness" relative to a physical or special attacker so that it will be easier to draw a line where we think 25f should be.Maybe it's a miss on terminology but I don't know if that was my conclusion.
So traditional Defensive Earthquake Mew is a check to Physical 25f (if given a free switch, it should win every time), and is not a check or a counter for Special 25f. We can move defensive Mew to a counter if we want, by simply ensuring we are always outsped by neutral univested Mew. It will never be a switch-in or wall, however; neutral damage is too stronk from this typing. We're talking sets today as they are played in-meta; of course theoretically the existence of 25f causes a new "Specially Defensive Mew" set with Surf/Scald/Liquidation and enough speed to exactly outspeed us to become meta just to deal with us, but the standard defensive set now is not that.
Double Dance Mew pressures both sets; it isn't a true check or counter due to too many variables, but if it still has its Z-crystal or if it's allowed to set up, there's nothing we can do to harm it before it explodes our brain with its powerful Psychic STAB. We thus would be cautious about coming in on a mutual switch if its Z-crystal is intact, lest we just die to Genesis.
Likewise, we can split Pyroak into two sets:
- Offensive Pyroak is a check to any and all builds of 25f; it cannot afford to manually switch into us, but it has the natural bulk to take a hit and OHKO with Earthquake if given a free switch.
- Physically Defensive Pyroak is a check to Physical 25f only; if it comes in on a move it will get out-actioned and out gunned, and it simply dies to Special 25f without causing much damage. With a free switch, however, it likely staves us off and wears us down with Giga Drain/Leech Seed/Synthesis, especially if we are using recoil moves.
- Neither Pyroak is a counter unless we are slower than it (not likely, given how slow Pyroak is), since it takes massive damage from switching in manually.
I think it's a fair thing to consider; we should make sure as we do final stat distribution that 25w can beat us as well. Most Water STABs do, but I think it's fair to say we want it to be a safe switch-in and true counter to us, meaning we'll need it to have the speed to outspeed us or the bulk to stomach (multiple) neutral fire hits. I am not TL, but I think it's definitely a thing we should focus on since 25f is going to have so much power and so few safe switch-ins.