Funny that you should bring that up. I'm finishing up a book about Ueshiba's aikido and how it compares to Modern Aikido, especially in how Ueshiba's "aiki" was different. Look for it soon.
From a Modern Aikido perspective, though, if only a very few people under Ueshiba ever got some of his "aiki", then how would 99% of the aikido world know what "aiki" actually was?
Some things to think about ... if you are training techniques and are relying on timing to make them work, that isn't Ueshiba's aiki. How many are taught to get out of the way of the attack by timing the movements just perfectly so that some kind of blending can occur? Great jujutsu, but not aiki. (That isn't to say that jujutsu is useless. aiki alone is not a martial system. You become aiki and then whatever martial system you choose, you express aiki in it. You still need jujutsu.)
Remember, too, that when Tenryu could not push Ueshiba over, could not get the better of him, Ueshiba stated that it was because he knew the secret of aiki.
Ueshiba and his peers (Sagawa and Horikawa) both noted that aiki was a body changing method, not a technique based method.
When asked what aikido was, Ueshiba replied, "I am aiki".