>>42026951I've played this game at a reasonably high level for 5 years and I've only ever seen one stall team with a Ferrothorn, which I beat on BW ladder.
Ferrothorn isn't a stall Pokemon because it just doesn't fit on stall teams, it hardly does anything to advance stall's win condition, doesn't wall any notable threats that other stallmons don't and has no reliable recovery.
That last part is key because stall relies on having all the pieces of its suit of armour intact to keep the opponent's offense at bay. The way to beat stall is by racking up chip damage and field conditions like entry hazards, and positioning your best wallbreaker/stallbreaker into the right conditions to do work. Eventually, the stall player has to let one of his pieces go, thereby giving another member of your team an opening later down the line. The better the stall player is able to preserve their HP, healthy status, and a side of field clear of hazards, the longer they can drag the game out to force their inevitable win.
If they run a Pokemon like Ferrothorn, or let's say defensive Landorus (another Pokemon new players sometimes mistake as a Stall Pokemon due to it being defensively minded), they're just giving up a slot on their team to something that can't recover and keep itself healthy. This is basically a piece of their suit of armour that is very quickly going to be beaten down by a competent player because it can't tank hits several times like Chansey, Gliscor etc. can.
Ferrothorn, Landorus et al are basically Pokemon which give the stall opponent a head start on their route to victory, because in order for them to accomplish anything, they have to weaken themselves and give the opponent essentially permanent progress in the battle, which is antithetical to stall's strategy.
