If you want to provide your feedback on products direct to the teams responsible for them, there is a direct way via a feedback form. This feedback goes directly to the team members. I can speak for the AutoCAD Team as one of those on the feedback list, we reply to much of the incoming email as we possibly can and also take it into consideration the provided feedback for future solutions and development work.

AutoCAD Team Feedback Form
Click Here

Bug Report Form
http://www.autodesk.com/submitbug

There is a feedback link on every product page at the bottom shown as "Contact Us".

Cheers,
-Shaan