finally beat xcom's main campaign so i can take a break and do some smogoning
anyway i honestly don't think garchomp's return changes much for stall. most stall teams in this era kind of need skarmory (you need the spikes, and mamoswine can really injure you if you aren't running something like skarm. slowbro is solid against mamo but it loses to boosting dragons regardless, unless it lands the scald burn), and skarm's position in the game was already established - it walls most physical dragons, except
1) haxorus aqua tail under rain, which can pack quite a punch. a boosted superpower can also hurt, and a taunt is catastrophic - PK's haxorus sets in the megathread definitely illustrate how to beat skarmory.
2) dragonite's sun fire punch
NEW - 3) garchomp's sun fire fang
garchomp's fire fang and dragonite's fire punch are pretty directly comparable in terms of whether or not they can be walled. because of their low base power and lack of stab, a physically defensive skarmory can take an unboosted hit from either one fairly well. LO would hurt a bit more but almost no physical dragonite that carries fire punch runs LO (lum/lefties is standard) and almost no garchomp carrying fire fang runs it either (yache is MUCH more popular because it works against offense teams where as LO is too easily checked) of course, if boosted (CB/SD/DD), or in sun, it can leave a lasting mark on skarmory, but a whirlwind and some roosting, if you can find the time for it (admittedly a challenge), can deal with that problem. a surprise fire blast from either one, even uninvested, will also leave a deep dent in skarmory, because the standard skarm right now is (has to be) physical. but that is quite rare - mixed dragonites are the only ones that carry fire blast and they're way down at the bottom of dragonite's usage. no standard garchomp set carries fire blast either.
anyway not to say that stall is more viable because of garchomp's return, because that would obviously be incorrect. mainly the point i'm making is that garchomp, in and of itself, does not change much for stall. skarmory was able to wall most dragonite before unless they had a strong fire punch or a surprise fire blast (which is extremely rare), same is true of garchomp. stall hasn't gotten any better, but it hasn't gotten much worse either.
the real problem with garchomp's return is that every time a powerful offensive threat comes back into the game, the popularity of offense goes up further, which will probably make it even harder to ladder with stall than before. oh well. those of us that were running stall in this metagame, we knew we'd be having an uphill battle to start with.