I like the syntax, you have made good choices. It appears this is an external program written in C++, how does it integrate with MediaWiki? It would probably be best to write it as an extension, rather than an external program. I suggest making it so that anything inside <template> tags is considered to be MTC code and is parsed by MTC before being handed over to the MediaWiki parser. (There are instructions for doing this on mediawiki.org)