I am very pleased to say that I got a fresh eye on "The Conduit" yesterday, and it really helped. This story had been hashed over by yours truly so many times that it felt dead. I couldn't even read it anymore, but this reader helped me see some obvious places that needed strengthening. Many thanks to Aika, and all the other readers who've helped with this story so far. The revision effort I put into it today made me feel more confident about sending it out again to face another possible rejection.
Advantages of critique demonstrated! However, I still haven't decided whether or not to join an online writing group. Some of the candidates on my shortlist are getting mixed reviews from other writers. I think I need to focus on discipline at the moment, to get more viable pieces closer to completion.