... if you want at least some indication of aiki versus jujutsu, just look to history. How many of Ueshiba's students had some very good foundations in jujutsu/judo of some sort? ... If you knew that the current practice of funakogi undo didn't train aiki in the least bit, then how does that make it valid in an art with the name of aikido?
... not in the least bit? Is this fact or infatuation ? Define the objective difference -- that's fact. Tout your shiniest enthusiasms -- that's infatuation. You haven't attempted to define the difference -- factually. It can't possibly work, simply because YOU could not make it work, or did not understand why it does?
Don't get me wrong, there is a difference, not a trivial nor a simplistic one, but it is not a physical mystery. There are legitmitately different ways of comprehending it. It is IN the kokyu undo. It is not lacking, languishing from lack of work on understanding mebbe -- but only because people are looking for some inexpressible mystery to be revealed by some kind master -- rather trying to master it ONESELF.
People mainly wanting to follow (or lead, for that matter) are, (historically speaking, since that is your measure) -- not interested in going out to find the objective truth, but in continuing to receive their subjective validation.
O Sensei demanded that we understand what he understood -- not that we follow his way of understanding it. Understanding is a conquest -- not a gift.