Dugtrio is going to dive head-first (body-first? does it even have anything other than a head?) between the trapping nerf and weather nerf, even if it doesn't take advantage of weather itself. Dugtrio's only function in OU was to trap ground-weak Pokemon, particularly on Sun teams. For anything else, Dugtrio is terrible. Like, really, really terrible. Not being able to trap Aegislash, one of the new premier Steel-types, is a huge blow to Dugtrio, and its niche in Sun teams of trapping Heatran and T-tar is basically gone.