I posted this last Friday, and unanimously, everyone decided that characters are the most important (except Morgan did add on "But it's SO Important to me that the plot is whole and complete... Gah. The never ending trial of trying to balance everything... How's that for a political answer ;)")
Mrs. C also said that she doesn't like unfinished story OR character arcs, but she added on that she got really upset when one character did not grow at all during a book.
Unfinished Character vs. Story Arcs? Which sucks more?
Characters Arcs are FIRST, and SHOULD (I try not to say must) be completed.
They are the most important, and the most revered. If you do characterization right, your book will be immortalized. Because, the point of a book is NOT "Oh, the goal was achieved!" IT DOES NOT MATTER. What matters is HOW the goal was achieved -- and that lies with the protagonist.
Would you get upset if cheating-robbing-murdering Bob solves the mystery in the end by cheating-robbing-murdering?
Would you get upset if Sydney Carton, in the end of A Tale of Two Cities, sat lazily on the side drinking alcohol while Mysterious Stranger saved the person (whom I shall not name due to spoiler alerts)?
Would you get upset if Dumbledore sprang up and defeated Voldemort, while Harry sat on the side and clapped him on?
I would. More likely, I would get annoyed and slam the book shut. In the above scenarios, the goals were achieved, BUT, it must be that the character arc is fulfilled at the same time.
The story arc is just a metaphor for the character arc. In order to fulfill the story's goal, the character must undergo the change he/she is scared of. The story arc supports the character arc. The story arc must change and progress as the character does.
Both arcs are REALLY important, however, I have yet to find a book which I like involving an unfulfilled character arc. I've read unfinished story arcs, and this is literary fiction at its finest, even present in mainstream fiction like Harry Potter and Titanic in the form of Whisper Storytelling.
The point of a book is not that the goal is accomplished, but that the character arc is accomplished. THIS is the Secret to, "Which is greater? The Character or Story Arc?"
It is the Character Arc. But, how can you have a cathedral without its supports? How can you reach the ceiling without a ladder? Build a FANTASTIC story arc, and put your character on top of it :) Then, you will succeed.
Hope I helped!