As far as I know, exact match domains (EMD) were not PUNISHED by google so much as any extra ranking boost for having the keywords in the domain name / DNS was eliminated.
Apparently t was about reducing low quality EMDs appearing in Search Results. Here are the last year's threads discussing this update: [webmasterworld.com...] and [webmasterworld.com...]
@graeme_p This one page domain - is that page what one could call low quality? I mean if you ignore the size of the domain and look at that one page being returned in SERPs as an answer to the query - would visitor perceive it as low quality? Does it answer visitor's query?