She is often considered to be "the queen of crime novels". The prize Agatha that writers of criminal novels can receive is named after her. She wrote more than 80 books and no, not all of them are about Poirot. Give her a read, the fuss about her is for a reason ;)

Your hypothesis has sense and I do believe that if I was to watch a remake before an original I would probably like it better but ONLY if it is good enough when compared to a book. I have found that remakes usually want to add an additional touch to the story and go to far with it :)