As a writer, I put a lot of stress on myself. I am constantly thinking, "Is this INTERESTING?" when I write. I expect so much from myself, and especially from a book written by a popular author.
That being said, to answer your question, "What do readers expect from any successful or popular writer?" - I expect an opening sentence that will grab me immediately. Kathryn Harrison who wrote a meloncholy book titled, "The Kiss" is a good example. Also Richard Paul Evans.
I am drawn to a book written by a successful author if done in the first person. I feel as if I'm sitting at a Cafe' with the author, and he/she is talking directly to me.
I also love a good quote at the beginning of a chapter. I like simplicity. If an introduction is twenty pages long, I usually do not buy the book. In my opinion, a one-page introduction is plenty.
I do not like books where I have to look up the meaning of words such as "inchoate," "fusillade," and "ennui." All these, plus many more, were in a book that I read, and I had to have a dictionary nearby the whole time. I don't know why, but I get turned off with the word, "plethora," even though I know it means, "excessive quantity."
All of this is my opinion only. I think everyone has their own unique tastes when they are searching for what they feel, is good reading material.
Blessings, Sparklea :)