As a hachidan in jujitsu, and an Aikido player for the past 20 years, it has become abundantly clear to me that if you don't understand ki development, you have very little actual technique. Since all techniques are "breath and timing", it is extremely difficult to execute anything without either.
Prof. David Shaner was one of Tohei's deshis, and I have found his training and his students to be quite capable of doing Aikido with anyone. Sensei Fumio Toyoda was one of my good friends, and also one of Tohei's students, but the styles and teaching of both of these guys was very different.
In all areas of martial arts, I've found people who tried to be "spiritual" martial artists, "technical" martial artists, and "combat" martial artists. There's a piece of each of that in all of us, and how it's manifested to your students is the perception that "your style" portrays to them.
You can trust me when I say both these men knew their stuff, and clearly no one had better technique than Tohei, or Osensi wouldn't have made him chief instructor of the Hombu. At the level they were, it is not uncommon to see different teachers from the same school separate to diverse teachings of the same skills. It doesn't mean that Tohei knew less, just that he focused his training in a different area.
Just as I have favorite techniques, they might focus on irimi, or koshi-waza as the base set of skills for their students, and teach everything else around those skills. It is up to the sensei to determine how and what he is going to address to the students, and it will come from their understanding perspective to the students. Just as your view of the same technique is different from different places in the dojo, how teaching is given to the students is always something with a perspective.
I'd be a little careful, however, before I accused someone like Tohei of "not understanding Aikido". I'm sure Richard Petty didn't know everything that ever went on in his garage, but he won 200 races, and I'd be careful before I accused him of "not understanding racing". Osensei didn't give Tohei that 10th Dan because he disagreed with him.