The energy difference between being solemn and jubilant is remarkable.  If you give energy, you will receive it back in kind, usually.  The meaning of Ellefson sensei's sig line is a reflection of this concept.  I really don't know what to think of people who bring a 'serious' attitude to the mat.  In some cases, this seriousness can even border on the grumpy. 

Back to the question, though.  I view O'sensei would probably disapprove of his heirs arguing about what aikido should be and would likely object to that being the source of division of the art and it's students.  He would probably advocate exploring each discovered interpretation for possible value.  A pioneer would do exactly such a thing.

I think that O'Sensei would not be displeased with the different interpretations of Aikido. His Aikido changed over the years, and I think he would understand why there are different "ideas" about Aikido technique. Is Aikido ever finished? Done? It is ever evolving and I think O'Sensei knew that it has to mold and change and evolve in order to blend with the changing world. I do think that he would have frowned upon the ego trips and politics that are becoming inherent in many organizations. I hope that is what he would feel. But then again, he is just a man, not perfect and he had some of his own political stuff going on. I think he would be proud with some of the great Aikido teachers and students that are out there though. In every art/profession etc there are good and there are bad. Okay, i'm just going to stop now, cuz i lost my train of thought and i'll just shut up now.

Faeth

"Be content with what you have. Rejoice in the way things are. When you realize there is nothing lacking, the whole world belongs to you."