>>54747303Shell Smash was never really that good in Doubles. It's way too risky since your enemy can double into your Pokemon easily or nullify its advantage with speed control. It was always a move better used in singles than doubles.
Technically, you can make most Pokemon work in VGC as long as you support them with 4 - 5 of the "top tiers". Even in the Top 16 in Worlds this year there were a handful of "oddball picks" like H-Arcanine, Zapdos, Baxcalibur, Chi-Yu, Roaring Moon, and Gyarados, but they're always supported by the other top tier Pokemon