For example, English Language & Usage's updated site theme is ready for testing! is perceived badly, where one of the reasons were the old design looking old-fashioned, including the Serif font.
Other site-compelling fonts include Open Sans on Graphics Design and a few other sites, and Roboto on Android Enthusiasts. The site-specific fonts are a special highlight of the sites. Normalizing them would to some extent normalize the user experience on those sites.
Can we bring back site-specific
font-family for individual sites globally (not just for titles and bodies)?