I believe anything short of 800-900 words is too brief but is there such a thing as excessive discussion-length? I don't want to bore the reader by being too lengthy.
Its depends on the volume of work you have done. You should put all the relevant points related to your work in discussion but you should not write irrelevant points not directly related to your work just to make the discussion part look bigger. That does not improve the quality of your work in any way.
Of course, I have discussed all relevant points related to my study. My concern is that my discussion is too in-depth and, as a result, not concise enough for comfortable read.