As suggested on gnupg-users (https://lists.gnupg.org/pipermail/gnupg-users/2019-February/061620.html), I'd like to request having an option to generate revocation certificate for subkeys (rather than the primary key).

Rationale:

Our use case involves signing key kept on a server for the purpose of
automated signatures. We'd like to keep the secret portion
of the primary key offline and use a dedicated signing subkey
on the server. At the same time, we'd like to be able to quickly revoke
the subkey if need arises without having to reach for the primary key.