2) If I remember right, WD removed more than some online services from the GPL firmware. I think they also removed most of the commercial 3rd party applications like the paragon NTFS driver, leaving you with ntfs-3g which has a poor performance for example.
WD states this quite clearly on their website:
Warning! This is the GPL source code. This is NOT the firmware for the device. If you use this source code to update the device, it will be treated as a third party user-modified firmware. We recommend using firmware released by Western Digital only. Using third party or user-modified firmware will cause malfunction and will void your product warranty. Once you install third party or user-modified firmware, even if the product is rolled back to the original firmware from WD, access to certain features will be disabled.