I was actually thinking we'd move them to a "subtool", like we do for the authorship stats. How does that sound?

I'd be fine with that; it would just be nice to be able to see all the page editors simultaneously, but it's not vital. It's just a minor annoyance.

Actually, looking at authorship, I was going to say the Top Editors section could probably be merged with Authorship, but then I realized they're measuring two distinct things. Top editors is measuring editors by edit count, which could be integrated into Authorship, but it appears to be using a different measurement of added content:

Added text is any positive addition that wasn't reverted with the next edit

While Authorship is using:

Authorship attribution of the current version of the article, measured by character count, excluding spaces.

Both measurements may be useful as distinct measurements. Although, for the purposes of reversion measurements, multiple consecutive contribution by the same editor should probably be treated as one edit (an easy tweak). In general, Authorship is probably a more useful measurement, except when the page is currently vandalized or has undergone controversial changes. The Authorship measurement is also optimized in ways that a local reversion search can't be, because local reversions require checking through edits that may be unnecessary for comparison with current content.

Overall, I personally would be fine if the current authorship measurement was retained and the reversion measurement was removed, but I don't think that should speak for everyone.

Thinking more on the reversion measurement, I actually like the idea of previous version evolution, if it was more refined. I think it would be useful if there were an edit-by-edit history that showed whether an edit was adding, revising, or removing content, and who's content in question was being affected in the case of revising or removing. This would help to see how someone's edits were specifically retained or slowly transitioned out, and would allow both good copy edits and subtle but harmful content removals to be identified (obviously, the tool would not be able to differentiate, but the tool could at least identify when revision of this sort was occuring). Although, we have patrollers for a reason, so while identifying these trends is useful when something is missed by a patroller, it's not vital.