Good point, but was thinking according to status/number of University teams also.
Extrapolating things out, have to wonder how Team Otago does relatively poorly in ASB Premiership with 2 top club sides (going by past Chatham cup results) Canterbury does well with lesser performing sides (again by past Chatham cup results).
If I can offer some insight, I'll say the senior base of players in the FPL, the stars for the 2 big clubs etc, don't tend to value the National League as much and off course many players are out of town. If Otago United was picked by solely the best 11 players in the FPL, it would be a much stronger team. Of the team that finished last season for Otago U, I would say only 4, maybe 5 at a stretch could lay claim to being the best player in thier position in Dunedin.