Yes, freezing the MotorolaOTA is the way to go. You may never get updates in future (even bug fix updates). But hey, you got root in 4.4, which is good, especially when unlocking BL is impossible.
If you really want to get any update in later stage via OTA, then unfreeze the same app and unroot your phone. Then accept the OTA, but you will loose root and may never gain again.