I don't think he was an enigma as much as he was just a bit patchy. Same with Diamond who now seems to be etched into the history books as a categorically awful player - yet I can remember plenty of games where he looked the business.
I actually thought he was pretty solid bar some poor patches of form which mainly came at the beginning and tail end of his time at the Dons. As you say, when he was bad he was rank rotten. Probably still a better option than any other CH options we have currently bar McKenna.