When a text is written, when it is printed for a first time, it will have a contemporary look. When you then look at historic texts, at a first publication, you will notice the many details that show its age. It can be in differences in orthography, differences in vocabulary and also differences in the layout, the fonts used.
When sources are published in Wikisource, maintaining the atmosphere of the original text is very important. It is why the original orthography and vocabulary are maintained and with the availability of the WebFonts extension there is a potential to use fonts that give this impression of age.
In the Office hours of the Localisation team, the question was raised if we could support cuneiform. The answer to that was that we can when there is a freely licensed font. We found a freely licensed cuneiform font and it is made available on the Wikis that support WebFonts. The bigger question however is about all the other scripts that are of historic significance. This is of particular relevance to the Sanskrit Wikisource; the Sanskrit language is written in many scripts and it is only recent when the Devanagari script became the default script.
For sources like the Quran maintaining the original orthography and characters is an article of faith. It is for this reason that characters were added to Unicode because alternate representations of the same characters were missing. We do have a beautiful freely license font, the Amiri font and we would love to support it in MediaWiki but we are struggling with technical issues.
For the Wikimedia Localisation team, it is impossible to identify all the needs for fonts, for historic text representation. This is why we have language support teams. They know their language, they can identify a need and hopefully they can identify usable freely licensed fonts. When they do, we can and will support fonts. In the mean time we will continue our work on a unified language selector. This will make the use of WebFonts easy and obvious. At this time it works, but it is hard work for you as a user.
Internationalization / Localization outreach consultant