Share is a different user interface to the underlying repository. It uses a different set of tools to get access to the Alfresco information and to display it. Hence, you don't really have to chose one over the other.
That being said, all of your list can be handled in Alfresco Explorer, but it may require some customization of the UI to get it just so. Also, Explorer provides a more detailed level of control over information than does Share. For that reason, you might want to consider providing Share sites to most of your users, the consumer grade, while anybody doing behind-the-scenes work would use Explorer to set up workflows, etc.
The third option is to roll your own interface. The Alfresco Share interface is composed in Spring Surf, a dynamic page layout tool that uses portlets and other presentation tools to provide a standardized interface. You can compose your own set of interface pages using Surf to present a custom web application for most of your users to use.