That seems like a misleadingly-broad term, but sure. IMO, public-key cryptography (or just asymmetric crypto) is already an improvement over "the Diffie-Hellman

That seems like a misleadingly-broad term, but sure. IMO, public-key cryptography (or just asymmetric crypto) is already an improvement over "the Diffie-Hellman key exchange," which is what's generally implied when talking about public-key crypto.