I think the Challenge has suffered (?) from an increase in the quality of images posted. This all started as a thread for folks relatively unskilled in photography to post on a topic and get feedback. For quite a while it was mostly a three dude show, but has expanded to attract photos from some of the better shooters on the Digital Photo forum. The higher quality of photos has reduced the c&c posts. I think.
I have cut back on my laundry list of ideas to give others more of a voice in the topic. I like the idea of debating for topics and felt that users were going with my suggestions too easily. Dreaming up outlandish ideas is one of the great parts of the creative process.
Overall, I still believe it has it's place here. Sometimes the Contest bogs down, sometimes POTD bogs down. Why should the Challenge be any different?
Fall/Autumn has been proposed, so how about Orange?
Dale