I've already submitted one (Jan 18 never heard back).
Sometimes one does hear back, but usually not, unless more details or clarifications are needed. Often, good Feature Requests just show up in an update or an upgrade. I have had a few of mine make it into the program, but have never had any contact. The requests are read, evaluated and then prioritized (number of requests by different users go a long way here), and then handed over to a design team if they "make the cut." In a very few instances (very few), an Adobe staffer will comment in a thread and at least tell us if some work is being done. They are necessarily tight-lipped on this work, but it IS nice to know that a request has been escalated to the team.
Good luck,
Hunt