Since physical branches are costly to operate worldwide, what does the future of banking likely look like?

Branchless Banking (be it the unbanked or banked). The future is certainly that the most of the transactions you do within a bank branche are now being juxtaposed on the mobile handset. With respect to deposits and payouts, you are now able to do this via ATMs, POS and agent networks.

Brett King has an excellent book called Bank 3.0 - a must read. See: Amazon.co.uk: Brett King: Books