The discussions are spread out over a lot of different channels. This post, as well as a few of the other ones about the HF are collecting input from the people in the community. GitHub has a lot of discussion as well. Some of the witnesses have expressed their views directly to Steemit. You are welcome to email Sneak (sneak at steemit.com) if you have anything you want to get to them directly - but they are already hearing from a lot of people, so no need to repeat stuff if it's already been said by other people before.