Surprisingly my state (the supermajority leftist CA) has not waived NCLB [1]. I have no idea what "costs" it would entail, but I see no reason why organization would agree to ludicrously unachievable goals like 100% passage rates - unless folks in that organization wanted it to fail (for political purposes).
As I understand it, the only 'cost' to getting a waiver is requesting it (and perhaps assisting with the 'period of review').
That said, I know that there were 'windows' in which to request the waiver, and it's possible that for whatever reason, CA wasn't able to get the paperwork ready in time for the last window?
It's also possibly related to political objectives, but at the same time, Obama is trying to get states away from NCLB, and CA is super liberal, so you'd think they'd have been the first to sign up?
[1] http://www.cep-dc.org/page.cfm?FloatingPageID=22