Before you make these changes, what do you want to achieve? (other people also are interested in that so a feature request / pull request discussion could help)
I would like to send/receive data from an MQTT broker securely (TLS). That's why I would like for example to block some options in the existing node (e.g. not to let any more the possibility to use an unsecured connection) and add other fields that would be useful in my development.