Rob was never a major character in the series. He was always looked at from a third person point of view, of from reports of actions. The major characters in the series was always the ones that had a point of view and thoughts explained. In the case of Rob alot of what happened to him was seen from his mothers point of view. She "survived".
Im pretty certain alot of the open plot holes will be filled in later, and alot of what seems meaningless now will become more apparent and fit into the story towards the end. Ive read many epic fantasy books, and the main reason it draws my attention is the fact that martin dare to do something no one else does. Essentially most people dont want to see their favourites suffer to a great extent, and people are naturally inclined to favour the "goodies". This is the reason you so rarely see tv-series or movies where the hero die, it would simply be to much to handle for the average viewer and result in low view-ratings.
If HBO actually go though with producing this series with one season per book, it may very well become the most awesome thing ive ever watched.. given they stay close to the books. On the matter of it being like a soap opera, I think you can compare it somewhat to the series Rome (which is sort of a soap opera).