Firmware updates are now available for the SWD lenses:
ZUIKO DIGITAL ED 12-60mm F2.8-4.0 SWD v1.2
ZUIKO DIGITAL ED 14-35mm F2.0 SWD v1.1
ZUIKO DIGITAL ED 50-200mm F2.8-3.5 SWD v1.1
The update info says "improved sequential shooting speed for use with E-5" but others have reported focusing accuracy and speed improvements as well.