Ive never been a fan of noticeably color-tinted (saturated?) background colors, if the pure b&w is unpopular id try something like discord's mobile app, with a dark grey as the background and some color as the accent.
Also i think having the corners of ui elements rounded more like in the screenshot looks worse.
The screenshot still looks better than every other web lemmy client though
i think i had a knee-jerk reaction to seeing the theme, i think it looks quite nice after using it for a bit, so im all for the proposed one becoming the new default as everyone else seems to prefer it, even though i prefer the old theme.
also having an "amoled" option in the color scheme dropdown that gives you the original theme would be cool.