I agree that technically you can have two non-orthogonal values and would actual satisfy some of the problems of users when switching fonts. Like a checkbox 'pr

I agree that technically you can have two non-orthogonal values and would actual satisfy some of the problems of users when switching fonts. Like a checkbox 'preserve x-height when changing fonts' would make those changes less drastic. Yet the article argues that font size is broken, my point is that author does not understands it's intended usage. Fonts are a very specific instrument with a long tradition of knowledge associated with it, yet there is context of a more 'consumer' setting, like using a code editor, here maybe there is a clash between professional usage (designers should be fine that different fonts have different size) and more of personal usage. Fonts were not meant for personal usage generally, and there is a certain learning curve on how to use them correctly, but there is no 'interface' currently for a general type of user who just want the text to look good.