You know, it's funny. I've only watched the pilot of the 60's so far and not other episodes, but I know the energy refilling scene you're talking about, and I remember distinctly thinking "Wow - they'd never get away with that in today's animation."
And then I started to think about why. Somewhere along the lines, it seems to me the culture (at least here in America) has turned things that used to be considered innocent and cute and funny and playful into something forbidden and taboo or even inappropriately sexual. And that makes me sad. I thought that was a really cute scene, and I think it would have been considered cute at the time, but is something people honestly feel almost a sense of shame about today because that's the cultural environment. Which really bothers me. (It's just an interesting thought to me if either of us would have felt that way back in the 60's when it aired, because my guess would be no.)
Anyways, you're not the only one who's watching all the series. I started with the movie, have watched the pilots to all 3, and now I'm starting with 2003 and working backwards (but slowly; probably over a few years - heh - had to take a hiatus for a few weeks because I'm so busy). Also going to read the manga soon!