O Sensei was pretty darn impressive even before he went on his whole universal love kick. This much I know.
After he started moving away from Aikijutsu and towards Aikido, he got "better" in some ways, but it is impossible to separate out whether the cause was his aforementioned "univeral love" philosophy, or whether it was because he was still training really hard, and getting old. Somehow, in my mind, oldness promotes good Aikido. You can't make up for flaws in technique anymore...
Anyways, it is literally impossible to answer this question experimentally, so we'll never know for certain.