The important thing here is that standard Spedef Gliscor will likely counter Salandit, so we at least have something viable (and not something niche and otherwise garbage). Although other pokemon can check Salandit, Gliscor is the only viable mon (iirc) that is ok with poison, and it also has a 4x super-effective EQ to OHKO back. It can be used for stall and balance I guess. However, HP Ice is a thing...
Here's a calc using Simisear vs standard Spedef Gliscor. Simisear has base 98 Special Attack and 75/63 physical bulk btw. I figure it's a reasonable pokemon to compare Salandit to, based on the dex saying its not very strong and whatnot.
252 SpA Life Orb Simisear Hidden Power Ice vs. 244 HP / 200+ SpD Gliscor: 260-307 (73.8 - 87.2%) -- guaranteed 2HKO after Poison Heal
0 Atk Gliscor Earthquake vs. 0 HP / 0 Def Simisear: 302-356 (103.7 - 122.3%) -- guaranteed OHKO
So if this thing has passable Special Attack and can outrun stuff like Gliscor, then Gliscor can't really win. However, with base 80 Special Attack (I used Klefki) it isn't quite as dangerous:
252 SpA Klefki Hidden Power Ice vs. 244 HP / 200+ SpD Gliscor: 176-208 (50 - 59%) -- 17.2% chance to 2HKO after Poison Heal (if leftovers)
252 SpA Life Orb Klefki Hidden Power Ice vs. 244 HP / 200+ SpD Gliscor: 229-270 (65 - 76.7%) -- guaranteed 2HKO after Poison Heal
Once again, if it's fast, then Salandit will be much more threatening, as it can cleanly 2HKO if it holds a boosting item. However, if Salandit has ~base 80 Special Attack and does not hold a boosting item, standard Gliscor will hard counter it.
All hail Gliscor, the hero the meta deserves.