Succinct is not how you would describe either Gravity's Rainbow or Anna Karenina yet I enjoyed both very much. Entertaining? No, but very moving and both impacted me deeply. So that is my answer. I like a book to impact me at the end of it not necessarily entertain me throughout it. Of course when I read noir fiction like that of the master, Richard Stark, succinct applies very aptly and those type of books do entertain.
Does it simply have to be entertaining, or impactful, or both?