The question is not whether another "opinion" is needed but whether that opinion is linked to a specific analysis of the book--pointing out specific attributes of form, style, or theme through quotation or extended description--that might reveal to other readers some angle of understanding or interpetation they haven't previously considered.In addition, I think writing one's thoughts down in this medium can be a way of teaching oneself. I know that I can have many ideas and impressions about a text, but it isn't until I flesh them out in black and white that I can fully comprehend the nuances and implications of these thoughts--which sometimes extend into even more illumination and ultimately lead to a better understanding of the text itself.
This ties in to what Darby wrote about "the notion of overpopularity." If you love something, why shut up about it simply because others already love it too? It isn't the topic or work that should be accepted or rejected, only the way in which we write about it. There can never be enough "specific analysis" of a text's merits.