Blizzard confirmed in a blue post that Darkmoon cards will drop from all types of content in Dragonflight.
(Source)
Hello.
We’ve definitely noted feedback on the initial leveling experience taking a lot of effort/time until you reach crafts that are useful.
It’s important to know that Darkmoon Cards will drop from all forms of content. The Darkmoon Booster recipe is not the only way to source them.
Is it intended that the darkmoon deck boxes do not have any main stat on them?
That is not intended. Darkmoon Deck Boxes will have primary stats in next week’s build.