I think the source of the blue problem is that to get dark enough blue on screen you need to subtract raw blue, that is the luminance column in the forward matrix gets a negative blue value.
Adobe doesn't seem to put negative values there, but instead let blue render much lighter than realistic, and in return get no negative colors in extreme ranges, ie a more robust profile. Phase One often do this as well, although I do see extreme blue clip to black sometimes if I remember correctly.
I shall investigate this matrix design method, that is avoid negative blue value in the luminance/Y column, it could be a problem solver. The question is if this can be done without sacrificing blue accuracy in the normal range... the LUT can in theory compensate, but perhaps not without too aggressive bends.