AVOS is ultimately at fault here. They didn't want to hurt the feelings of the Delicious old guard, so they made it sound like everything was ok. But everything -wasn't- ok with the product those users fell in love with, it was being obliterated. The best thing AVOS can do now is help users come to terms with the present reality.
Ultimately, the re-launch was the right move - the delicious of 2004 cant survive in today's web. But AVOS's communication around the transition just wasnt frank enough. They should have just held a funeral.