Do you all remember Long Zheng's http://www.aerotaskforce.com/
It's was organized and developed solely for figuring out which changes most of us thought needed to be made. I know Long thinks it wasn't much but I think it actually made a difference because complaining on forums doesn't help at all.
Hey there. I know it made some difference, people inside Microsoft told me so, but there was/is a cost to running a site like that (not server cost) that doesn't pay off very well now,
If I were to relaunch it, I'd basically need to redo the site to fix all the functionality/usability/security issues that were lingering around. Nearing the end of the service it was also susceptible to spam/trolling (non automated) that was a bother to administrate.
Currently I don't have the time or drive to do this for free and Microsoft already pays a lot of money to companies like UserVoice (where they host their Windows Phone feature requests http://windowsphone.uservoice.com/forums/101801-feature-suggestions and other products), so I can't really convince anyone to fund any future development.