Upgradind USB 2.0 to USB 3.0 possible?
I have the same Mac Book and I use Nikon Camera Control Pro 2 over USB 2.0. It works well enough. Some day I will replace this laptop as the battery only lasts about 30 minutes per charge.
I have not tried the express card conversion, but I have a Mac Pro desktop with a CalDigit 3.0 card added. While the card works fine with other peripherals, it causes a computer crash when the D800 is plugged in.
I would be careful about adding a third party USB 3.0 as it may or may not do the same for you.