(The WB deals would certainly seem to put a stake () in those rumors following the failure of the pilot to be picked up which claimed that the WB thought the pilot had been terribly cast. But then, it's often wise not to believe at least half of what you read - particularly when said rumors are unsubstantiated and sources "who choose to remain anonymous" are cited... )
I don't think the quality of the 2004 pilot or it's actors really had much to do with it not being picked up, honestly. If you look at what happened during that time period last Spring, not only did the WB not pick up the new DS but they also dropped the planned Lost in Space remake (which they paid big $$$$$ to do) and canceled Angel for no good reason (It's audience had GROWN since the previous year and was getting ratings higher than Buffy had been getting it's last season). They, also, went against tradition and did not preview any of their new pilots for test audiences, instead making decisions internally - the decisions being to approve a slate of teeny bopper soap operas and reality shows.
The effects of that decision making are being felt this season, as most of the new shows are tanking.