I'm not interested in watching it again, but my impression from the last time is that he's about 3/5ths of the way to "true monad nirvana" if such a thing were a place. There are higher levels above that where we start to really understand the category theoretic and PLT theoretic mechanism of monads, but I think that's truly a different tier.

From watching half of it, he mistakes monads for being a trick to avoid Io, which is not true. Io really does happen in Haskell, it is just contained. Also he mentions types not being necessary to understand monads, but immediately launches into a description of the bind and unit functions by, you guessed it, stating what the types of the function's were and what kinds of things they returned (I.e. the exact thing he said he wouldn't talk about on the previous slide).

That being said, I liked his reworking of bind to be a method on an object. I agree monadic computation is tedious to read when you don't have an infix bind operator, and his trick of turning bind into a method solves that pretty well in a language like JavaScript.

I think he's probably overstating the case that what he calls ajax chaining is always monadic (but what most of us who didn't write a competing library would call jquery style method chaining). I would guess most implementations of this kind of APIs do not adhere to the monad laws.