That's exactly why I think an Imperial Armoury-like books, but completely based on AoS, would be one of the best things for the game:
Use most of the AoS models.
Resin/plastic kits for characters and big and weird stuff that wouldn't be part of the main AoS game.
Books about themed armies (aka, subfactions and world building based on stuff that is not part of the main show).
And being part of the specialist team, they don't have a regular pipeline to follow (at least, not as strict as the Main Studio). Just let Matt Rose take a look at the rules before going to print...