Thanks to users "filmmusic" and "Bubblegum" at the Blu-Ray.com forums, here are some comparison screenshots between Angel's Egg on DVD and Blu-Ray versions. The BD versions do show more detail and resolution, better color balance, and sharper picture quality. Click on the photos to see their full size, and the differences will become more obvious.
I think I'm feeling nostalgic for 1980s anime films, the ones that predate any computer graphics or modern visual effects. I miss that purely hand-drawn look, like rough pencil sketches style. Drawing lines in animation became too fine and narrow when digital technology took over. Everything looks too clean. Ya know what I mean? I want something that looks like an actual pencil or charcoal pen, paired with an actual paintbrush. Analog. That's the word I'm searching for. These older movies look analog, not digital.
More screens below. First screenshot is Blu-Ray, second one is DVD. Click for a full-size view.
(Update: Redid the screenshots. Better now.)