I would like to offer the counterpoint that I didn't see a ~20% loss but an increase according to recount.

When I did my heroics pre 3.0 I was around 1100dps now that 3.0.2 hit I am sitting at 1300dps.

Do you have any +haste stuff? I am not sure but I have a feeling that this has something to do with my increase in dps.