David Schnarch's approach is complex. You have to read the entire book, not a snippet or an interview. I started reading it 6 years ago while looking for help with problems, and put it down. Just recently, with my outlook having changed, I read it straight through and soon go into his approach.
All of the clients and examples in his book are dysfunctional, or they wouldn't be hiring him. But he doesn't waste his time with people who are not committed to marriage. He is not a fix-it coach or technique coach.
Most people here would be happy to get back to mediocre sex. Schnarch and others are about moving your relationship to a much higher level. Schnarch focuses on passionate love, others address the entire package, where sex is just an essential component.