Of course some might argue that they need not rely upon text alone. They heard things directly from the source's mouth, or at least their teacher did. However, if this produced a common understanding, why did so many say that O-sensei's dissertations were virtually incomprehensible and why the seeming disparity in interpretation and meaning (especially generationally) why the all fuss?
This is really why I stated in another article I wrote that it's really hard to say that there has ever been any one thing that constituted some sort of orthodox Aikido.
Shirata Sensei would certainly be considered one of the Aikido Greats but his training was far different than Saotome Sensei's.
People on the mat at precisely the same time saw, heard, and understood what was taught completely based on what they were prepared to see based on their individual natures and natural talents which were clearly quite divergent.
Saotome Sensei tried quite hard to understand the Founder's spiritual teachings while attempting to translate them for his students into something more contemporary.
I have read interviews with other deshi from the same period who said that, at the time, they mostly day dreamed through the lectures and waited their turn at ukemi. Now, after a lifetime of training they've decided they missed something valuable and irreplaceable, regretting that, in their youth they hadn't been ready to hear the message.
Some deshi didn't care then and don't care now.
So whatever we learn about the Founder through the efforts of people like John Stevens. the Bieris, and our own Peter Goldsbury, what we end up understanding will be completely informed by our own practice. You will have a different take on it than I will. Koichi Barrish will have a different take on it than either of us. People with deep backgrounds in non-Aikido arts will have a different take on it all as well.
In the end Aikido will be as we make it. Personally, I want to do an Aikido that O-Sensei would have respected, whatever that is. My studies help me guide my training. But in the end, my Aikido will be mine and no one else's. I don't expect the "fuss" to stop any time in the future. But since the info we have about the Founder keeps increasing, ones perspective can change over time so I don't expect in ten years to understand things the way i do now nor do I think I will understand the Founder the same way either.