Like many other people who have posted, I was also unsatisfied with the ending. However, I do not think it calls for another book to answer the unanswered....if questions were going to be answered then they should have been done in the final book. Everything else is down to the readers opinion(use your imagination guys!)
Still, I have not had enough of the hunger games and I would love to here more about Finnick and Annie, Peeta's side of the story and how the hunger games begun. Those are surely more interesting than another sequel that may also leave readers wanting more?