I think that they're likely to wind up at some sort of hybrid list - where Arcane, Divine, and Primal lists are for spells that everyone (who has access to those lists) can cast, and then smaller exclusive lists for each class (this way they avoid much of the repetition) and then even smaller lists that are accessed by subclass.
One of the goals here is to make it so that they can easily package sellable spell cards with less SKUs than the current GF9 class-based ones (it is telling that the Arcane one outsells the rest of them by a wide margin) - it's the only one that ISN'T class-based!)