patience and understanding
I've never seen anyone do aikido waza like O-Sensei, and I'm not sure that he would want people attempting to try. Koichi Tohei was one of O-Sensei's top students, and the aikido of the two men appeared to be as different as their personalities.
As with music, students must first learn the basics before they can perform. Once they can perform, some may move ahead to composing.
The same principle must be applied to aikido. Students must first learn the basics before they can perform. (O-Sensei said there were 3,000 basic techniques in aikido and 16 variations of each technique.)
After students master the basics, the possibilities for genuine innovation within the art certainly exist.
Going back to Koichi Tohei, I've heard it said that he developed his ki curriculum for Americans, because, at that time, Americans had no concept of ki. So, rather than just trying to talk about it (like many people attempt to do on these forums), he developed a teaching method whereby Americans could learn to use and focus their ki with the help of a series of simple exercises. This, I believe, was quite innovative on his part. But mind you, he was 10 dan at the time.
I think that for young students who have yet to master the basics of aikido waza, attempts at creativity are humorous and sometimes even dangerous. It's like someone who just got their drivers license, attempting to compete in the Indy 500.
In the end, aikido is a concept. It's much more than the basic waza that we practice. Yet, once the basics are mastered and the concepts behind aikido are firmly grasped, the possibility for genuine innovation and creativity certainly exists.