Is BIP 32 Technology Cryptographic Curve Agnostic?
Any Elliptic Curve could work in the BIP32 scheme. The only property of a Curve that BIP32 relies on is that a * G + b *G = (a + b mod N) * G, which is true for any Elliptic Curve. 

Secp256k1 is a 'Koblitz' curve, which just means its choice of parameters enables very fast scalar multiplication (computing a multiple of the Generator point). 

With that said, if a vulnerability was discovered in secp256k1, it's not like everyone could just switch over easily. That would require a major change to the Bitcoin consensus system, and require coordination of many software systems.