But for people with macs, I'm assuming there will be a lightning to thunderbolt cable, so would this arrangement be faster than lightning to usb2?, else why the lightning connector, is it JUST for size reduction?
It can't be any faster, the bottleneck is in the flash, not connector.
They moved to the new design because they needed something smaller to house everything in the smaller case. it is also reversible, and can probably be updated to USB 3 when it makes sense.