regarding using/developing, reporting issues (bugs/usability issues) or requesting new feature, what are the obstacles in front of users to let their voice be heard?
what mechanisms and communication channel you wish to have?
I think the obstacles are much less than you'd encounter with a closed-source project. For the ones I'm involved with, the main obstacle is that the user needs to subscribe to a mailing list, a forum, or to sourceforge or github to communicate bug reports and feature requests (when we allowed anonymous requests we just got a huge amount of SPAM and the legitimate submissions got lost in the noise). But we watch things like Stack Exchange and even Twitter as well.