To clarify: Starting in October, Flow will be maintained; it's not being abandoned. Further work on the discussion system will need to be driven by communities voicing their desire for further work on it. Additional development on the discussion system will be prioritized on community request and on a project by project basis.
As a pattern that we're all familiar with, it's more likely that people will comment when they have negative or critical feedback, particularly at a centralized forum. While it's helpful to point out things that are not user-friendly or are frustrating to use, it's also helpful for the team to know what is going well - so we can do more of it. I’d like to encourage people to speak up (here or onwiki) when there's positive feedback as well – this goes for article-editors as much as software-developers. There are people on many wikis who have been happily using Flow, but they haven't gone out of their way to broadcast that information off of their usual home wiki. What do you like about this software? Is it headed in the right direction, even if it doesn’t seem complete? Are there things about it that the Collaboration team could continue to focus on?
See also, the thread on wikitech-l, for additional discussion. http://thread.gmane.org/gmane.science.linguistics.wikipedia.technical/83889
Hope that helps