It's really a horrible use of the admin bar by plugins if they're just adding stuff just because they can. I have a single plugin that adds a new item to the admin bar. It goes under the "Add New" menu item for adding a new role (Members plugin). It would make no sense for that item to be under a "more" menu item.

The better option is educating plugin authors about when it's appropriate to add items to the admin bar. For example, there's really no reason for plugin authors to add links to their settings page to the admin bar.

Context is more important for items in the admin bar. By adding a "more" item, we're inviting plugin authors to add even more crap.