H.H.Munro (Saki) has a defined writing style that has maintained its popularity due the witty, quick, and sharp execution of the dialogue and the character dynamics in each of his short stories. As a realist, Saki uses conventional elements of storytelling to treat themes such as naivete, feebleness of character, human weakness, and practical joking, among other typical stamps of everyday life.
This being said, "The Open Window" reunites the very traits that are typical of Saki's style of writing. In fact, "The Open Window" is one of the most memorable of Saki's short stories precisely because it seems to define his style more so than other of his great works. However, the popularity of this particular story may be due to its twisted ending, which moves away form the modern realistic traditions of writing.
Yet, though the story does not need alterations of any kind, it would not hurt the plot too much to add more background information on Vera. Although critics of "The Open Window" find it unnecessary to write a long analysis on such a short story, the reviews that have been published seem to coincide in an overall curiosity over her character. Critics wonder whether Vera is a fiendish individual, or just a bored young girl. For example, a review by John Daniel Stahl makes the conclusion that
Vera not only rejects but completely—and one might say, maliciously—dominates the feeble representative of adult life who crosses her path.
Yet, this assumption is based on the same information that every reader gets, which is still open to interpretation. The fact is that there is no other resource to understand Vera. There is no inkling as to the nature of Vera's stay at her aunt's house, or why exactly she she feels the need to frighten Frampton Nuttel. The only information provided is that she enjoys this kind of thing, for
romance at short notice was her speciality.
Therefore, Saki could have added perhaps one paragraph to dedicate to Vera, and maybe explain in it what prompted her visit to her aunt (Was she expelled from school? Was she on vacation?). Maybe a little more info on Vera would leave the reader more satisfied as far as the rationale of her actions.