The WordPress admin bar has been of great use. Here are some suggestion from me :
1. Anyway, the bar is using up space, so add all(or most of) the links in the dashboard to the admin bar. This can help navigating faster.
2. Provide a feature to the admin that allows them to disable the admin bar for all the other users or user-groups.
3.This might seem too much, but please try to add a tab in the admin bar to quick hide and open the bar.