It's a good painting, but with such an unreasonable amount of hype, the real deal can only disappoint. You can't even really engage with it as a painting, it's become some kind of inescapable weird hyper symbol of Great Art (tm).
St John the Baptist gets me far better than Mona Lisa. And as you say, the drawings are kinda where he really shines.
I like to think that for a guy with so many different talents and pursuits, doing all these repetitive, careful passes over what was ultimately commission work to pay his bills was less engaging than the rapid, iterative nature of drawing. Technical and precise, yet ferociously vivid.