I just attended a talk but Sumit Gulwani where he demo'd FlashFill, FlashExtract and walked through their underlying architecture. His talk had much cooler demos than any I could find online but from what I can tell it seems like they provide a superset of transformy's functionality (not to detract from it, this is very cool, and I'd be curious to see how related the underlying theories are). Apparently current work by that team at Microsoft is focused on abstracting out functionality into a system called FlashMeta so that it can be applied to a bunch of domain specific problems. Overall very exciting work, from both parties.

Do you know if this is available on the new Excel for Mac too?

No. The shortcut does not work, nor is the menu entry in the "Fill" menu.

It's one of many missing features.

Nice, Excel really is one of the most undervalued pieces of software, it has so many details like this and it handles almost anything you throw at it. Pivot table is another of the lesser known features that is hard to live without once you've found out that it exists.

Given that Excel runs many, if not most financial organizations at a practical level, I'm not sure that it's undervalued in practice.

Excel is to finance people as terminals are to developers. When getting bug reports from end users, we've even had them delivered to us as screenshots embedded in Excel files.