Bio not provided
The idea was proposed as a way of getting the expansion out faster. It was proposed that it was better to release the rest of the expansion, without raids, than to delay the expansion further through raid testing. Testing could then be done while the expansion was shipping and raids be released via a patch a couple of weeks in. In the end I don't think its been necessary to consider it because raid testing is happening whilst other systems are not available for testing (like pet battles).
I don't really have a problem with this one way or another. I definitely think it would be better to ship the expansion earlier and raidless if those were the choices! Its not like you couldn't easily fill a short break pre-raiding with gearing and all the other cool stuff. But I think in terms of publicity, it would be a disaster (I think I'd have to avoid the forums until all the raid content was out because the level of QQ and hate would be even more depressing).
Better to release a small amount of raid content with the expansion and then gradually put out the rest and present it as 'staggered' access ;) (not suggesting that was what was done before, but it would look better from a PR point of view given they have done staggered access before).
11 months, 4 weeks ago on Idea: Release Mists with No Raids?