i have not seen a single form of reliable counterplay to gliscor actually get listed in this thread. having to run substitute on every ground resist just so you dont get fucked by this thing (all of which still risk losing to SD variants) is not very healthy in the long-term
You don't have to, that's just an option. Gliscor is exploitable with setup sweepers because of its reliance on protect. If Gliscor goes for a swords dance, as long as you have an anti-setup mon (Gliscor has a pretty meager attack stat, so you could even afford it getting to +4 if you have an anti-setup option), you can just beat swords dance.
In fact, if you think about it, there are situations where a mon does not beat all sets of another. Great Tusk doesn't always beat Kingambit, Iron Valiant has effectively next to no hard counter, stored power sweepers can run coverage for common checks, and so on.
Your options for beating Gliscor are definitely beyond "substitute on a ground resist."
Yes, substitute on a ground resist is definitely a thing as a check, and other checks could be taunt users and setup mons.
As for counters, you have Corviknight, Hatterene (even IF Hatterene gets knocked, it still beats hazard setting Gliscor), take heart Manaphy, and magic guard Clefable as options for pretty much every set, and then options such as air balloon Heatran and air balloon Gholdengo for non-knock + earthquake sets, and then for non-toxic sets (which are somewhat rare), Great Tusk, Ogerpon-Wellspring, Zapdos, Enamorus, and RIllaboom can beat those.
A common argument against these options is that many of the counters can be toxic'd or knocked. However, Gliscor has an annoying case when selecting its moves.
Gliscor has to run protect pretty much, or at least every serious, non-pivot set does, and then if it wants to be a support option, it should have spikes or some hazard. From there, there are really 3 options for the last 2 moves, which are toxic knock, toxic earthquake, and earthquake knock. Even if you don't account for Gliscor's sets, you probably have at least some usable counterplay against Gliscor, at least by figuring out the set.
second off, i think losing defog and roost were, paradoxically, both net benefits for gliscor. if it hadn't lost roost, it's likely that we never would have truly rediscovered how annoying protect spam is on a mon that heals that much, especially when roost is much easier to pp-stall than protect this gen. having defog would turn gliscor into the meta's premier defogger due to its general splashability and capability to take on ghold, which would mean it would run spikes less often (because as good as it is, gliscor has a bit of a 4mss problem, so if you're in the market for a defogger you might as well run one of the other ten million spikes setters and use the defogger that matches perfectly into… spikes gliscor), and it matches up so well into other hazard setters that the hazard meta would become less of a problem overall. so my theory is that gliscor managed to find a fucking behelit sometime between gen 7 and the dlc and the loved ones it chose to sacrifice for power were roost and defog
No???? Gliscor definitely took a blow when losing roost.
Yes, protect sets are and have been usable on Gliscor for a long time. People have used protect in gen 5, for example.
I also think people would have considered protect due to roost having only 8 pp, but all of this just talks about why losing roost doesn't matter.
The real downside of losing roost is that it really does make specially defensive sets a whole lot worse. Yes, they are viable to some extent, but as it feels right now, specially defensive Gliscor feels like it just takes a bit too much damage from everything. You still don't get one shot by ice spinner Great Tusk, but at that point, why would you want to take one?
I know a lot of people have mentioned Gliscor coming back from incredibly low HP, even if you don't KO it, but this is, in practice, difficult to pull off against teams that do have decent offensive pressure can naturally force you into tough positions, such as setting up on a crippled Gliscor, force you to make awkward switches that lose you momentum, or sacrifice some of your other mons' HP (or even sacrificing them entirely) if you really want to do such a thing.
I know, people have seen Gliscor go from 1% to 100% during the course of the game (I have seen it firsthand too), but the truth is that the cause of these scenarios are teams that allow this to happen because they are really fat, such as the xavgb fat team or stall, or they were played poorly.
In my case, I saw a tera blast ice Cinderace deal 99% to my Gliscor on my reqs alt. Here, my opponent should have tried to keep up pressure by getting up rocks and, since now my primary Cinderace answer was severely crippled, use Cinderace to snag some damage on my team. However, my opponent failed to do this, which ALLOWED me to get my Gliscor to full HP.
This is also, in theory, incredibly similar to regenerator; if you don't kill something with regenerator outright, it has a very real possibility of just being able to rejuvenate itself throughout the course of a game. In fact, this is even easier to do with a regenerator mon, considering that regenerator outheals rocks or 3 layers of spikes, doesn't require you to waste a turn on protect (so you can just switch out immediately after taking your HP), and has an overall greater burst healing.
If Gliscor had roost, however, it would very comfortably be able to run specially defensive sets because it has a button to press that just undoes the damage it takes, making it an incredible wall from both sides, even if roost PP got halved.
Despite this, I will give you defog Gliscor because I do think defog Gliscor would be sick. However, people would still complain about its ban because now, you would still very much see Gliscor mirrors, and they would be even more common. Now, one Gliscor is spamming spikes, while the other is clicking defog every 2 layers of spikes to keep hazards off. The hazard stack aspect would be nearly utterly neutralized, but not the Gliscor mirrors aspect.
I will say I wish Gliscor kept defog, as it does seem like a nice defogger into Gholdengo as well, but that's besides my argument.
