>I see no reason to honor the so-called “default line-height”. It’s basically a font designer’s personal preference, imposed on every user of the font in every viewing condition.

Erm... To a large extent, these details of a font _are_ the the designer's -personal-preference- professional judgement, and that's the point. We use different fonts because they have a distinct feel or quality, and how much spacing they have between lines is one of the many little details that add up to the gestalt of a font. If you don't like the line spacing of a font, don't use it. Or tweak it if you like. But don't pretend that declaring that all fonts should have a line spacing of 200% of their cap height isn't similarly trying to impose your personal aesthetic preferences on everyone else as well.