I have reviewed the cutscene for The Scions of the Seventh Dawn. It does -not- state that the Echo helps you from being tempered. Yes it states that it is vital to combating the primal threat but that is implied to be the fact that this gift allows you to transcend the racial, ethnic, other boundaries that will allow you to work with the Beastmen.

"Measures must be taken - measures which transcend boundaries, be they of faction, race, language or creed. And to do so, Scions require those with our talent."
Nothing in that cutscene says this will allow you to fight primals without being tempered! otherwise, so many of those in the Path and Minfilia should be fighting too.