I play the Semi-Slav as Black vs. 1.d4 and I would like to know how much demand there would be for me to make a high-quality Semi-Slav repertoire. I've already had some requests for a Black vs. 1.d4 repertoire, so I thought I'd ask.
Regarding quality, if I make this course, I think it's fair to say that the size will be similar to "GM Rafael Leitao's Sicilian Najdorf" and the quality is likely to be similar to "1.e4: A Comprehensive White Repertoire" or "Crush the London!".