Is the 'cryptography' package a hassle to integrate? The quotes I gave say otherwise.
From what I hear it is also simple to use.
If that is your goal, then you need to make a persuasive argument that there are usability problems with the existing libraries (even those libraries which are designed to be easy to use), and that your package will be easier.
Is there any reason to not build an easy-to-use package on top of, say, the 'cryptography' package, perhaps by using the 'hazmat' subpackage?
I do not think that "building your own crypto is `the root of evil`". I don't know who you are quoting. The original Biblical reference assigns that to the love of money.