this is a big question in the education feild where i live as well, but that is another story
So anyway O-sensei was a great martial artist (for now we'll just let that stand if you disagree please start another thread)
He devoted himself to the study of many martial arts, and trained like extremely hard. to get to his level of skill. then he created Aikido that we study, however, i feel that sometimes we focus too much on how he was like at the end of his life or the result of all his training without taking into account the process that got him there.
What can we achieve without that process
The research that has been done does not support your theories. Morihei Ueshiba devoted himself to only one martial art: Daito ryu. Ueshiba merely dabbled in a few others and never actually learned any of them in any significant way.
Also, Ueshiba never created aikido. Literally, the way of aiki. That honor belongs to two other men. The aiki of daito ryu would be from Sokaku Takeda. The reinvented, reimagined aiki of Modern Aikido would be Kisshomaru Ueshiba. Morihei Ueshiba followed the way of aiki as given to him by Sokaku Takeda, merging it with a spiritual ideology of his own design. The name "aikido" was given by a Japanese organization and Ueshiba acknowledged it.
Lastly, the aikido that most people study is not from Morihei Ueshiba. Trace the weapons training in your dojo and it most likely won't lead back to Ueshiba. Trace the tanto training and it won't lead back to Ueshiba. Trace koshinage and it won't lead back to Ueshiba. Many of the ki exerecises won't lead back to Ueshiba. Do you have spear training? Why not? Ueshiba did so. Aiki solo exercise training? Yep, Ueshiba had them. Were you told about contradictory energy? Why not, Ueshiba trained them. Etc, etc, etc. Far too many things different.
If you truly want to know the process, do the research. Then get out and train with people who have already done the research and are training it. Right now, there's quite a few out there and more appearing all the time.