Completely with you. I've played with limited syntax highlighting in the past (class names were blue, to answer the question in TFA), but for the past few years I've been running with plain black-on-white, with only a green highlight for comments, and a subtle yellow for strings.

https://i.xkqr.org/lighttheme.png

I think the relatively bold highlighting of comments is important – lots of times I'm the only person to react to incorrect comments because people's themes blur them into the background and they stop reading them.

(But then again, I'm crazy. I colour diffs blue and orange: https://i.xkqr.org/blueyellowdiffs.png inspired by similar advice in https://jameshfisher.com/2014/05/11/your-syntax-highlighter-... I think it has worked to help me notice things other reviewers have not, but it's hard to know for sure.)