No, their first priority is protection of their own IP which they must defend vigorously. Any unofficial "blessing" or slack with that takedown can be used as a chink in their case to retain the IP at a later legal engagement. Rather unlikely, but the law is not filled with many absolute certainties.
I'm certain that the first comment from Blizzard (and not their lawyers) to him was "We apologize for the takedown, but we have to cover our bases. Now, please tell us more about your project. We're a bit curious..." Once actual intent is discovered and identified, I'm willing to bet that they've extended a formal notice of approval to allow him to continue work, and posting videos in the future. Mark my words, in a few days that video will be back up on youtube.