Add Granular User Security Restrictions to CRM

There doesn't seem to be any admin control for granular security in CRM, any CRM user can access anything, although it cand be considered useful information why does every user need to access purchase information for your suppliers, the marketing tab should be just for the marketing people and key sales people involved in marketing. Any user can destroy the web forms or campaigns you have spent ages setting up.
At the very least you should be able to turn off the tabs on the left for certain users.