This construct has a much worse bug. It separates the TLS from the rest of apache so it protects against bugs in other parts of the server (HTTP parsing for example) but it doesn't separate the TLS session code from the crypto primitives, so it wouldn't protect against heartbleed. For that forking at the PKCS#11 boundary would be much safer.

Thinking about it a better OpenSSL patch than the Akamai one of protecting the memory with a different alocator would be to run the actual crypto in a different process with a well-defined IPC between that and the main library. That would give you much of the safety of a software HSM without any changes to Apache/nginx or any other TLS server.