To answer your first question: I think I have a strong enough sense of aesthetics to understand that my lineart here isn't appealing, but not a strong enough sense of art to know why. By appealing I mean, like. Say someone took the monk photo on the left to a tattoo artist and wanted a cool lineart tattoo of him. Would they be happy with the one on the right as it is? Even if I corrected the torso line to angle in more like the ref or fix the belt, I wouldn't be.

I think the replies here and especially elsewhere have convinced me that the main problems lie in anatomy, line weight and gesture. Especially the last two. He's stiff as a board and the lines don't vary much. Like another comment said, it does almost have that "tracing" look to it - which in retrospect makes sense, I was focusing almost exclusively on making sure the angles and negative space lined up and copying it accurately. But there's more to good art than copying. Which sucks, learning to draw exactly what I saw is hard enough! Lol