But that applies to everything in Aikido today, since none of it has gone through an academic peer review process, including the statements by direct students of Ueshiba - many of which are contradictory.
But some of "it" has been handed down through the teacher-student interaction. This by itself doesn't guarantee quality or fidelity of the material passed (to say the least) but you do know the provenance.
Personally I would have liked to see something like academic peer reviewed evaluation applied on the inherited "it" but I am not holding my breath. If you bring fresh "it" from the outside the system however, well - then the burden of proof is on you.