Basic cryptography isn't really that difficult compared to the Bitcoin blockchain
I think that's 100% backwards.
Blockchains in general only use crypto 101 concepts. "Crypto" has been overloaded to mean cryptocurrency stuff when really the mathematics we use in our systems are barely scratching the surface of actual cryptography... "It hasn't been peer reviewed"?, more like "it has almost nothing to do with it to begin with"
I guess it depends on which crypto techniques you're talking about. The stuff in that particular class doesn't look significantly difficult. I think the difference is that crypto is already invented and they are explaining algorithms which are old, problems which have been solved, there usually is a book you can look through to find all the math formulas you need.
Now you look at Bitshares and there is documentation, there is a systematic way to figure out how it works, and you're right the crypto parts are routine cryptography, but on a conceptual level and on understanding all the potential attack vectors I would say it's very hard.
You have a good argument when you say Bitshares may not be similar to Shor's algorithm or Shamir's secret sharing algorithm for instance. But if you look at a blockchain it does something unique which is not described in any book on computer science or cryptography really. I think people are underestimating the effort of building a functioning cryptocurrency from scratch, in my opinion the Cryptography 101 class is easier. I suppose the hardest parts would be the discrete probability math but if you can write the sort of code to make up Bitshares I would say compared to that it's trivially easy work.