I believe he's had this star trek podcast for at least a year, he just plugged it on Dragon Talk. Fairly normal, he's mentioned it before.
I'm fairly sure it's not Crawford's call. The MTG team is the bigger, even more profitable fish, and they are clearly uncomfortable with crossing the streams too much. They even have said they don't want to do another D&D card set for the main line (I know they're doing the side line for Baldur's Gate), despite the D&D cards being I think the most successful ever?
Anyway, I believe the MTG team isn't keen on having D&D lore collide with and cross-over with MTG lore. So no melding of universes, no Liliana Vess going to Forgotten Realms or Elminster going to Ravnica. They seem fine with sprinkling references here and there, and doing a D&D product in MTG and vice-versa. But actually melding the two lines into one lore seems very out-of-step with everything published so far.