So, who are the aikido lineage holders? I am not asking who the closest students were, who the most popular students were, or who anyone thinks most represents what O-Sensei's aikido. I'm not even asking whom O-Sensei authorized to teach. I'm asking who received transmission. Whose aikido is certified as a complete understanding of what O-Sensei had in mind?
AikiWeb threads are replete with arguments, however polite, that are rooted in fundamentally different understandings or partial understandings of what aikido is. So, I'm suspect of any complaints about instruction; is the complaint that the instructor really is an idiot, or is it that either the methodology of instruction or the material being transmitted does not match the a particular interpretation of aikido instruction?
No one. No single person got the whole deal. I have not talked to a single former uchi deshi who claimed to have gotten more than a part of what the Founder taught. Each picked up the part that fit his interest, inclination, and talent. That's why getting out and training with more than one teacher is important. Each can show you something, none can show you everything.
That said, each of us, based on his own interest, inclination and talent has certain teachers he thinks really have the goods. I have come to realize that the teachers I am most attracted to have turned out to be all in the Yamaguchi lineage. Saotome Sensei, Endo Sensei, Gleason Sensei, all trained with Yamaguchi Sensei and share certain common attitudes about training as well as many elements of technique in common.
Other folks would probably pick an entirely different set of teachers to whom they look for information and explanation. They could be so different from the ones that I named as to be almost doing another art. That's why the search for a teacher is so important. They will not all take you to the same place.