> Is there a rationale for the deficiencies laid out in the OP Yes. The previous package had a dependency on the general purpose math/big package which was not

> Is there a rationale for the deficiencies laid out in the OP Yes. The previous package had a dependency on the general purpose math/big package which was not constant-time and had a large surface area (that was not required for crypto). This has lead to security bugs in the crypto package.