Compared to many of Poe's other stories, The Masque of the Red Death seems very slow and tedious. The descriptions of the various apartments, the windows, the lighting, all seem unnecessarily elaborate for such a short tale. Nothing much happens until the tall, gaunt stranger appears--and then there is no dialogue. In fact, there could be no dialogue because there is nothing inside the "habiliments of the grave."
The only aspects of the plot that work fairly well are the opening and the ending. In the opening it is interesting to visualize such a huge number of people isolating themselves to escape the plague. In the ending the silent, spectral figure offers dramatic tension but this is not sufficiently developed. Many aspects feel forced and artificial, including the descriptions of the entertainments and revelries. Poe is sometimes guilty of over-writing, which I would define as the equivalent of over-acting. He seems to be showing off his vocabulary and his eloquence to impress his readers. Poe also seems guilty of writing about things he knows nothing about, except perhaps from his reading. I suspect that this story was written in an attempt to recapture what Poe had envisioned in a dream--perhaps in a drug-induced dream. I am reminded of Coleridge and De Quincey.