from what i've read, "better than the Canon 24 or 24TS" is not a great recommendation
if a variety of rangefinder lenses of demonstrably better quality can be adapted to Canon full frame cameras, and Canon can make a very good to excellent 24mm, why can't (won't) they make at least one excellent rectilinear 18, 19, or 20mm prime? it doesn't have to be f1.4 or f2, it "just" needs low distortion, good color, and sharpness compared to the rangefinder lenses
i think most photograpers paying for a lot of pixels will be willing to pay for glass that can make use of those pixels - offer a "L+" line with Leica quality and quality control