I've read many people getting angry over this series because of several points:
-The focus is mainly Sarashina and Tachibana's relationship, it's place in society, how they both see it and the POV from Nana and Kaoru and how they see their own bond.
-This series it's not going to use the baby S&M you see in the original, the focus is heavy on the truth (that sometimes we might forget that despite being 'mostly' treated with so much heart and warm in the original) that in S&M someone gets hurt and someone is inflicting that pain.
-A bit more focused on the feelings than anything.
-If the author doesn't pull a 'Escaflowne' then we are seeing the foundation for the future relationship between Nana and Kaoru.
-Again, the focus is heavy on the emotions. Not just from Nana and Kaoru but also from Tachibana and Sarashina, thus several chapters focus more on the later.
Like with the Original Nana to Kaoru this is a beautiful series if just a tad more liberal when it comes to nudity and sex and a lot more angsty, a great follow up of the original but if you were expecting suddenly seeing Nana and Kaoru in a relationship . . . well don't hold your breath. They have many issues to solve before that.