Instead of lumping lead and contact management together, please add a Leads tab. Some preliminary thoughts: People marked in the Contacts tab as Prospects or Leads would be added to the Leads tab. The existing Pipeline view could be duplicated and repurposed for leads, showing by default Prospects, Uncontacted, Contacted, and Closed. Users could click into the leads to edit their fields, and when leads are closed as a qualified leads, they would be automatically converted to Deals. The tab should also allow managers to assign leads to team members and users to rank leads, changing the color of their border for quick reference as to which leads are hot, warm, and cold.