Hey all. Not sure if everyone or anyone has figured out a fix for this, but I was able to on my end. First, you'll need to be updated on all ends, System 10.10.3, Final Cut X 10.2.1, the newest Sony plug in and the newest firmware on your X70. The firmware update from 1.02 to 2.00 is what I was missing but there is still a catch. You will still not be able to import into FCX if you simply insert the card into your reader or copy from the direct folder that you copy to your hard drive. The key here is to remove the folder that says "XDROOT" and place it in its own folder. This folder cannot contain anything else, only the "XDROOT" folder. Then, once in the import menu in FCX, go to that new folder that contains the "XDROOT" folder and you're set. Import works perfectly and you can gaze into the beautiful eyes of 4:2:2 10 bit.
Here are some links to the updates.
http://www.sonycreativesoftware.com/pdzk-lt2
http://pro.sony.com/bbsc/ssr/micro-xdcam/resource.downloads.bbsccms-assets-micro -xdcam-downloads-XDCAMSoftwareDownload.s…
That should be it. Enjoy