I already posted why I don't believe Aurumoth is risky at all, and argubly fails the concept, which makes it pretty difficult to answer capefeathers questions, since I don't really think Aurumoth helps us answer them any better. I will answer bmbs questions tho!!!
Did you feel that you were able to collect wins more consistently using a single or several different sets?
Personally, I mostly spammed Quiver Dance the entire time. A pokemones "best set" is subjective but imo Quiver Dance was head and shoulders better than most of the sets Aurumoth could run. For example I wanted to try a DD + WoW lure set where I could lure out counters to Dragonite by using DD, then burning the revenge killers so Dragonite can have an easier time. But honestly, I just switched to Quiver Dance because it just slaughtered everything and was imo a better set. So to answer the question, using a single set I could was very easy to collect wins.
How do you think Aurumoth affected the metagame?
Well, the usage statistics answer this question, but I did see a lot of people limiting the pokemon Aurumoth could set up on. For example, I stopped running Tentacruel simply because I couldn't cripple Aurumoth if it switched in, and due to it being so hard to revenge, I just added Head Smash Donphan instead simply to limit the ease of it setting up.
How do you think the absence of Quiver Dance would affect this Pokemon's performance, particularly with reference to Weak Armour?
If Quiver Dance was not a part of this CAP, I firmly believe there would have been a far more diverse range of sets being used. Aurumoth has such a diverse movepool, but Quiver Dance outclassed so many sets, which sorta made it difficult to justify using a different set, like trying to justify using SD Landorus instead of RP Landorus. It wasn't impossible to justify, but it was difficult to do. Without Quiver Dance, DD sets might have been common, and I personally would have felt far more inclination to test lure sets, or more defensive ones (or Scarf Final Gambit or something), especialy as DD isn't quite as strong as Quiver Dance (DD can be countered, while Quiver Dance doesn't really have much).
I ask the last question because this is one thing I was really interested in learning from this CAP, in terms of how Quiver Dance affected it in terms of risk. In my own opinion, we could perhaps have learned more had we not had Quiver Dance - but then again, possibly Aurumoth would have then been rendered unusable, at least as a sweeper. Or would Dragon Dance have simply usurped the role?
Quiver Dance made it not really risky (along with No Guard) simply because Quiver Dance is a
safe move. There is no drawback, like Shell Smash perhapes. Quiver Dance boosted its SpA to massive levels (letting it 2KO Jellicent with Psychic), boosted its speed making it hard to revenge kill, and finally boosted its weak special defence stat, letting it tank powerful special attacks with ease. This last point is very telling, simply because the number of special scarfers that can revenge Aurumoth is
tiny. I ran calculations and heck, I don't even think Scarf Keldeo can revenge kill under rain if SR isn't up (and Moth is at +1), and its one of OUs best scarfers atm. Even ignoring revenge killers, the special defence boost lets it tank Scalds from Tentacruel from ease, as well as other special attackers (provided it can Quiver before said special attack) making it very easy to set up to +1, or even +2 if you used Illusion right.
The question as to whether Aurumoth would have been unusable as a sweeper should it have lacked Quiver Dance is an interesting one, but not something I really put high importance too, the goal was not (unless I am mistaken) to create a powerful sweeper, merely a pokemon that helps us understand risk and reward in pokemon. Sure, lacking Quiver Dance might have made it unusable as a sweeper, but on the other hand, a case can be made that Quiver Dance "breaks" Aurumoth anyway, so I guess the point is moot. DD sets would still have seen use I think, even if they might have had a harder time sweeping, I doubt that it would have overwelmed other sets as much as Quiver Dance does, but I guess its hard to know how it could have turned out.
Its getting late now (midnight) and this post is long enough already and I think I am losing my train of thought / thread here but I want to address Weak Armour in the absence of Quiver Dance. It is possible the ability could have gotten more use (I personally believe it fits the concept best but w/e) but the fact of the matter is, No Guard at least, with the possible addition of Illusion, are more reliable, they are safer, less situational options. No Guard for example, is safe, there are no drawbacks to using it, and it boosts the acc of all the moves I use (yay now I don't miss with Focus Blast / Hydro Pump). Sure, you can claim that the risk "is that your opponents moves are now accurate against you" but Christ, are you really switching into your oppoents inaccurate super effective moves (which was brought up time and time again in support of No Guard) regardless. So anyway, No Guard and Illusion are move reliable, more safe, and are "stronger" abilities (especially when you factor in that Aurumoth already has + spe moves in DD and Quiver Dance further decreasing the effectivness of Weak Amour).
tl:dr
Blame Birkal for introducing me to the delights of tl;dr posts