I’ve recategorised this topic to “extensions” since the goal of CommonMark core is not to introduce new features.
For reference, see the Markdown Extra abbreviation syntax is discussed here, but as @PeckishSnake mentioned, it applies to every instance of the abbreviation, leaving no option to exclude particular instances from being marked up. So I think a case-by-case abbrievation syntax would be useful, and I personally like the proposal here.