Feature summary:
In articles schema, I propose version.count field which would have the number of revision this article has, at the current revision of the dumped article. So a completely new article with only one revision would have count == 1.
Use case(s):
When you are updating data based on a new dump, you currently have only version identifier available so you can know if article changed or not since the last dump. But it would be also useful to know how many versions are in between as a proxy for how much has the article changed (imperfect, but still).
Another use case is to know which articles are more "active" than others. More edits mean also in a way more important article.
Benefits:
Reading historical data of articles requires many API calls, but having a bit of high-level statistics (like number of revisions available) can already be valuable.