Probably quite a bit of self depreciation on Matt's part though given that when he decided to quit his boss essentially said, "Why don't you just, you know, take some time off to think about it?"
I'd say someone with Matt's background and general mannerisms - even at GS where eccentricity and raw intellect, for lack of better descriptors, are traditionally valued - would be a significant outlier.
I worked at GS and I think the only people that fit the Levine mold were in weird structuring desks, like Matt was. In particular, PFI had quite a few characters that remind me of Matt. Ali Meli, who left GS recently and was written up by Bloomberg, comes to mind. Clearly intellectually above others with weird, interesting perspectives on things. Also given leash to go dream up and do weird and interesting things.
I don't think people like Matt actually have much value add in most areas of a modern investment bank, unfortunately. As Matt says: banking is boring now. I don't see how someone like Matt would succeed is traditional banking - or a flow trading desk - over the "average" GS employee who studied finance at Wharton or whatever. Most areas of banking strike me as having become very commoditized or routinized and outliers are viewed as more apt to cause tail risk than anything.
You probably noticed at GS that a risk desk won't put an employee in front of a book just because he got good grades at UPenn.
Investment banker here.. "Wall Street" is a pretty big concept, not unlike "Silicon Valley".
So in the best banks and the best groups, yes – I'd say he's among the very best, but there are plenty of similarly smart people around.
Having said that, I obviously have no insight into whether he was actually good at all the other things that make a great "banker". To stick to the same analogy, one can be a prolific coder but be absolutely terrible about writing docs and tests, keeping a sane git workflow, prioritizing, communicating, being a team player, etc.