Sounds great - kind of a no-brainer, for the MediaWiki accounts in any case. The only challenge I would see in the long term (in particular when extending it to other less specialized accounts) is that it might seem pretty repetitive after a while unless one crafts a custom message each time highlighting some of the content of the new issue - is that the plan? (Or include a such a custom headline in the newsletter itself, kind of like the Signpost's weekly Technology reports used to have.) FWIW, for the Wikimedia Highlights, I'm using the TOC for this purpose when posting on FB and G+.