That being said, my friend's response is not entirely inaccurate either. The internal power (aiki) possessed by Ueshiba Morihei is undeniable, yet somehow seems lost in transmission. This could be due to numerous factors, including Morihei himself. After making the final transition from Aiki Budo to Aikido in the years following World War II, his disdain for war and combat was so great he eliminated any references to brutality from his art. He began teaching in metaphors, using poetic terminology to describe what he's doing rather than breaking it down to his basic anatomy. Ueshiba Kisshomaru, Morihei's son and successor, did not have the military experience of his father and could not have fully understood the coded message Morihei was putting out. It's when Kisshomaru took over after his father's death that we really see a rapid progression from devastating throws that force uke to fall to choreographed demonstrations where uke jumps into an acrobatic roll for dramatic effect. No one understands why they're jumping, just that they were told that's how you respond as an uke. But ukemi serves a much greater purpose. When certain joint locks and manipulations are applied correctly, and with combative intent, the only response is to whip your body around with the motion of the joint twist or risk it being snapped like a twig. You were rolling not because you were told to, but because you had to in order to save the joint.
The problem is you have people trying to emulate the bodily responses of Morihei's uke without understanding the advanced internal methods that he's applying throughout the technique to make them work. Therefore, aiki gets downgraded to simply mean to blend with the attack seamlessly and cause off-balancing while remaining relaxed. While kuzushi on contact is an important part of aiki, it's only one piece of the puzzle and how you create the kuzushi may or may not internalized. Therefore kuzushi in and of itself is not aiki, as proper off-balancing methods should be present in all jujutsu ryuha.