One of the best places to go to see EOS's feature list growing or to make it grow, is the wiki. I'm much more inclined to support a feature when store owners and interested support/programming vendors put some time into design up front.
Another location involved will be the issue tracker, as we become better at posting the issues we are addressing before we code them.
Mantis maintains project road maps and change logs based on posted issues and issue states. This can give a pretty accurate picture of where development has been, is and will be - provided we use the features. This is made more powerful by our use of svn hook scripts to automate posting of commit messages to issues impacted by the commit.
Another interesting Mantis feature that the community can use to guide feature selection is the sponsorship system. Putting cash down on features of importance to you can help speed development and is a powerful indicator of just how important a feature is. The system also allows the community to spread the cost of development. Traditionally osCommerce based feature development has depended on programmer charity, or single source custom projects. This could allow for rapid deployment of feature sets that are useful by broader sections of the community.
David