The Premier Bankers at BofA are responsible for handling more affluent customers. Those customers must meet a certain set of criteria... $100,000 annual income, certain profession (Doctor, lawyer, etc) and a few more.
The Premier Banker acts as the "financial advisor" for that customer. Since they have few clients, they more actively manage the customers portfolio than someone in the banking centers. They will open accounts, do loans (including certain mortages), and certain investments like annuities. They can give their premier clients special rates on CDs and loans along with lower fees on certain items.
They generate business by not only getting referrals from the banking centers, but are also responsible for getting business themselves by making some outside sales calls.
As a Premier Banker you will have aggresive sales goals just like those individuals in the banking centers. Sales goals will be based on deposits, loans and investments. I know several people that moved into the premier world at BofA. Some of the loved it and some of them didn't. Those that loved it seemed to do really well at meeting their goals and getting the incentive.