Having got reqs, I got to see the meta without Dugtrio quite a lot. There are a few things I've noticed, in a general sense I can reduce them to the changes in Stall, Offense and Balance.
Stall is still very much alive and well, even without Duggy. Teams are falling back on Diglett or Trapinch (mainly Diglett in my experience), which for the most part do the same thing as Duggy - trap one threat such as Lele, Hoopa or Zard X and free up the Stall player to sludge their way through a 2 hour shitfest. There's been a resurgence in banded Weavile, and a lot of teams are just saying screw it and forgoing a trapper in exchange for something like Unaware Clef or Alomomola. Overall Stall really hasn't been heavily dented in the new meta and I would expect it to come back in full force regardless of whether or not Duggy gets banned. With this in mind, with regard to stall, I would say No Ban, because it is clear that Duggy is a catalyst, not the cause, of the power of stall.
Balance has changed significantly but also subtly - if you're looking for the changes you see them everywhere. You see a lot more instances of Tapu Koko and Lele, Heatran, Nihilego, even Pheromosa which some may find unexpected, but Duggy definitely hampered its usage. There are some Pokemon which are seemingly on every single team now - Fini, Volcarona, Metagross, Magearna, Muk-Alola and Excadrill are in my experience shooting up in usage, while there are a lot of Pokemon that have seen significant declines. In my 63 games plus many more on other alts, I have not seen one Double Dance Lando, Buzzwole, Tyranitar, Pinsir, and strangely no Rain teams although I chalk that up to chance. I've noticed significant declines in Tangrowth, Manaphy, Gyarados, Celesteela, Protean Gren, Mega Scizor. It's only been a few days and clearly people are trying to use teams they previously thought were weak to Duggy, but I've enjoyed this meta a lot more than in the past when I play Balance. It's clear to me that matchup is no longer winning 70+% of games and skill becomes a much bigger factor in many games. As a result, I think I would want to Ban Duggy due to the net positive effect on Balance.
Offense hasn't seen much change in structure, but has become more effective. I used a heavily offensive team in getting reqs and found it to be much more straightforward in strategy. There was no longer a clear win con that you can't use because Duggy would kill it, and there was no longer pivots like Magearna that were mostly or entirely useless when the opponent had a Duggy. Balance and Offense heavily overlap this gen, so it is not a surprise that Offense is benefited when Balance also is, but I truly have found that for improving many of the issues this gen has brought forward for Offense, a Ban for Dugtrio is the best choice.
Overall, that's 1 No Ban, and 2 Ban, so I will be voting to Ban Dugtrio.