I take it you talked to the top guilds and asked them why it took longer? Could not have been the fact most of the top are running 3-4 groups filled mostly with alts and funneling all the gear to the mains and that they are testing out how the final release of the machanics were over a couple of days and number crunching / comparing logs from all the raid groups... Noooo clearly it was just that it was too hard and the normals made them wipe non stop!
corelation without cause... always the worst way to look at data!