I notice you used the word "saw" to describe the manner in which you received first-hand information at Dan's seminar. My apologies ahead of time for asking redundant questions in the event you've already explained in greater detail your experiences at the seminar -- so feel free to reply with (a) link(s) vs. another drawn-out description -- but to what degree did you take ukemi first hand from him, and did you stay for the whole seminar? I ask because there are a handful of people in Hawaii who've met Dan out of curiosity, but just briefly to get a quick glimpse or hands-on sampling to satisfy their curiosity, yet have drawn the same conclusion about its ties to Aikido (i.e. without attending the entire training to fully learn about the theory and how the method, body movements and skills logically integrate into the waza and other fundamentals of Daito-ryu, Aikido and many other arts). However, to my knowledge, there are 0% detractors when it comes to the quality and significance of the skills and power (which I don't see you disputing, based on your experience).
That said . . .
I don't think anyone would dispute the representations of the aiki-jujutsu/do stalwarts like Takeda, M. Ueshiba, Sagawa and Horikawa as dojo/gym rats -- in particular regarding the tanren that developed their respective IP/IS. And, it's a credit to Ueshiba that so many aikidoka have worked so hard for decades, regardless of individual interpretations of aiki and its sublime properties, to attain skills and abilities akin to what he had following his example of daily earnest training.
If you've attended a full seminar, then, though I'm a skeptic of your and others' skepticism
, I respect your individual conclusion regarding flavor, and personally I'm not in a position to debate that since I'm not an aikidoka (well, outside of IP/IS training anyway) or Aikido historian.
However, regardless of the degree to which you, or anyone else in contemporary Aikido, has had mat time with Dan, how many Aikidoka taking either position regarding this topic have had mat time with Ueshiba as input for their conclusions regarding flavor? As previously mentioned, Meyer Goo, a seminal figure regarding Aikido in Hawaii who trained with Ueshiba while O-Sensei was visiting here, decided to meet Dan this past November. Meyer's original intention was reportedly to just be one of the tire-kickers to whom I referred above -- yet, upon taking ukemi from Dan, decided to attend the entire training, and decisively concluded that Dan's IP/IS are the same flavor as those of Ueshiba. From Meyer's perspective, I'm not sure you can put a price tag on that re-discovery.