I think that, whatever the change is to be, it has to be backwards compatible. So I think it should be treated as an addon.
As an addon, you may or may not use the info returned by dsl_status, and will not break some other apps (or scripts that someone has already made) that rely on the "legacy" behaviour.
If you implement that as a forced addition, then you could break some other apps that rely on it.
If implemented with another whole command, or as an aditional argument to dsl_status, it's the programmer's choice. Just select one way or the other.