Was Takeda the founder? I thought he was merely the next successor.
I don't know.
But, let's take a look at both. If he was the founder, the questions are still valid. If he was merely the next successor, well, the questions are still valid. Ueshiba still broke away from him at one point.
But, let me go back to your original post:
I have two questions.
Why is there such a focus on what O'sensei studied pre-war, instead of what he desired to transmit post-war?
My second question then, is, what was O'sensei's wish in terms of transmission?
My questions weren't designed to elicit answers from you, but rather to get you thinking about your original two questions. Why such a focus and What was Ueshiba's wish?
To start answering those questions, you should have information to form an intelligent base. Getting that information isn't always as easy as listening to your teacher. For example, there are time periods when no one knew that Ueshiba's main study was Daito ryu. Stan Pranin brought that to light. So, what other information has yet to be brought to light? There is quite a lot of information that hasn't been translated or shared. And some of the translated material has a spin to it. Sometimes not much, but sometimes a bit more.