Dr. Melfi was hot, and an integral part of the show as far as I was concerned. I don't know how I'd feel about her parts if I go back and watch as I haven't done that. Still, there's relatively few things that stick with you over time, and what goes between Tony and his doctor after she's assaulted is Good Stuff. I can see how that part of the show might be slowing things down for folks just interested in the ganster stuff, but it's the modern day "normal family life" stuff that makes The Sopranos what it is, IMO.
I think for today's audiences at large, The Sopranos provides the insights into a life most will never experience in the way that The Godfather did in its time. These are not Italian immigrants (for the most part). These are Americans of Italian ancestry (yes, only a slice), and they struggle with being Americans right along with everyone else.