Maffblaster and I had a small talk on it on IRC, but didn't finish it yet. Right now, Maffblaster is looking into a more flexible way of referring to other articles on the wiki (through the See Also sections). This method takes an article-provided paragraph as part of this source.
Now, the suggested paragraph is a new parameter (Article description) which provides a single-sentence description of the article. However, we already have the means to provide this (through the metadata abstract).
I would rather not introduce another parameter, but instead use the abstract one (which has existed for a longer time). The feedback Maffblaster (correctly) gave was that the abstract one often uses longer paragraphs, whereas the suggested parameter would use a single sentence.
I don't think there is really a need to differentiate on this. We can easily update the abstracts of articles to have smaller paragraphs, nor can we enforce that the other parameter would use a single sentence.
The reason why I prefer to keep it to a single one is to ensure that the number of non-visible parameter fields that we want to put in the article is properly managed, and that editors don't get the impression they have to provide the same information twice, trice, etc.