This would allow cards to be automatically introduced in groups, rather than the "just give me 10 new cards every day" thing. It could also allow a default suspended deck style, where all but a few cards begin suspended, and they are unsuspended in an orderly way based on one's progress with the active cards. That could be a pattern that works for drilling hierarchies of knowledge.
There's a deck style called the KOFI (conjugation first) system for learning Romance conjugations that would really benefit from that, which now depends on people manipulating the decks manually with the aid of an abused deck description field describing that manipulation.
Anki is pretty hostile to order, because spaced repetition is all about moving individual cards optimally and without regard to other cards, but the order in which information is introduced can be important. At this point you can only choose between introducing cards in a linear order, or completely at random. There's no way to deviate from that without the user having to learn to juggle things manually. A deck creator can't just suggest a schedule programmatically, even if the deck was designed around that schedule.
The other half of this, where cards that duplicate combinations of other cards are automatically strengthened when their related cards are strengthened (or vice versa) is interesting. Seems like a neuron model.