For the parser itself, there is work being done on something that's more structured. The new parser lets you round-trip from the wikitext to the generated HTML and back, which means that it's entirely possible to work with wiki content by just manipulating a DOM rather than having to work with the wikitext yourself.

https://www.mediawiki.org/wiki/Parsoid/Parser_Unification

There’s also this page:

https://www.mediawiki.org/wiki/Alternative_parsers

For context, the parser I'm talking about in my first post is Parsoid on that list.