I don't think there's much you could do to make The Sopranos more interesting, but having Melfi use him to go after her attacker I feel would have introduced a really interesting angle.
also my voice-to-text thinks that Melfi us "milfy", which isn't wrong.
"Tony... the man I spoke to you about... he was killed."
"Dont ask Doc. If something happened to him, he had it coming. The how or the why isnt something that will help you. Cause if it wasnt me you might be disappointed in me and if it was I'd never tell you."