The issue with Shedinja stall is that it hinges itself upon a Pokemon that is vulnerable to so much and then the preservation of it, which arguably distracts the team from normal progression in the game. Additionally, this gives the opponent ample opportunity to break through as there's one less defensively synergetic member/the aforementioned stress on Shedninja, almost defeating the purpose of using this stall over normal stall simply due to the degree it finds its effectiveness compromised.
I personally would only use the standard stall with Toxapex, Chansey, Skarmory, Mega-Sableye, Clefable, and Dugtrio or some variant of the double defog stall with Alomomola, Chansey, Skarmory, Dugtrio, Zapdos, and Clefable that is a bit more accustom to the release of Mega-Medicham. However, it is entirely possible that you can create or find other consistently effective variants of stall if you try hard enough!