Sherlock as Devdas, John as Paro, Irene as Chandramukhi. There's already an interesting amount of overlap here. Wouldn't have to be a complete adaptation. Any combination of that story with these characters would be utterly heartbreaking.
The creative choices and performances in Sanjay Leela Bhansali's beautiful 2002 film version [ https://en.wikipedia.org/wiki/Devdas_(2002_Hindi_film) ] are the closest to the show's dynamics, I think. Of course John as Paro would be quite different, though equally strong-willed. Doesn't take much to imagine our Sherlock as SRK's Devdas, haha.
Devdas crossover
The creative choices and performances in Sanjay Leela Bhansali's beautiful 2002 film version [ https://en.wikipedia.org/wiki/Devdas_(2002_Hindi_film) ] are the closest to the show's dynamics, I think. Of course John as Paro would be quite different, though equally strong-willed. Doesn't take much to imagine our Sherlock as SRK's Devdas, haha.