Yes... But why then is the aikido curriculum just so? With a repertoire of thousands to choose from, he instead threw a whole bunch out and gave us ikkyo, iriminage, shihonage and etc?
I believe there can never be a truly finished 'product' to be bought or sold at the dojo. The finished product is you and you get to complete the package. But what you put in that package is going to define it, cat food or dog food. A mixture is just that, plain and simple.
Pure rubbish and an incomplete thought process from the start.
None of what you say is factually correct or even logical to anyone who has the slightest knowledge of Ueshiba's training experiences and research. Your founder did everything you are railing against; it was exactly his going out to other arts in order to develop his own. He continued to research and continued to develop.
You see his art as a finished product, and that he knew best for you... he obviously never thought that way or even took on that role. He encouraged people to develop their individual way of aiki.
Were I you, I would consider that genius is not stagnant. Followers of visionaries rarely do as well. They lag behind and never catch the original fire. He knew it and tried to break his own mold for others to catch on.
The majority of followers are not visionaries, instead they opt for a pallid substitute and sadly think it is all they are personally capable of and keep pointing to the past to validate their present state. It's easy not to excell when you convince yourself that you can't exceed the model you placed before you.
Aikido can be so much more than it has turned into. It can be one of finest arts the world has known, but it needs a serious shift in focus to do so.