I think the name changes are only of historical interest and don't designate any fundamental shifts in Ueshiba's approach to his art.
That there was a gradual change there is no doubt, a change which reflected Ueshiba M. himself not just the influence of his son who I think often gets a bum rap.
I personally prefer the aikido of his earlier students but that's just me however, even my teacher was sent by Tomiki to live with one of Ueshiba's later students for six years to learn excellent technique. I think the aikibudo/aikido distinction being made is a false construct.
I believe it is a 'human construct' that only discusses a certain level of experience. The thing that isn't highlighted as much in discussions as history are the realizations of nature that O'Sensei experienced and was profoundly transformed through. These are not historical experiences, but personal and phenomenal experiences. They are moments of re-defining all that went before and putting them in to practice. As in the quote,when was aikido developed.....'when I was born'. You could still do all the same moves, but with a new realization they can become fastened to another level of knowing. And through practice this exchange of form and insight become a continuous cycle. That is how I know I'm doing aikido and not just waza. That is the remarkable element of aikido, for me. Same moves, different understanding.
As for Kisshomaru Ueshiba Sensei, peoples poor attitudes towards him remind me of the bumpersticker "If you haven't thanked a farmer, don't talk with your mouth full."