In order to simulate corps assets, could you not simply make some template variants with an added artillery batallion (or whatever) and switch your divisions on the fly between templates? It might be fairly pricey in terms of experience, depending on how many variants you want, but perhaps not.
I'm not a game developer (sadly), but IMHO to model corps assets more accurately, you'd need a number of things, all of which would take up a chunk of very-limited development time:
First, you would need a persistent OOB so that there are some actual corps to which you could assign assets. So far (yes, yes, pre-alpha) I've seen no indication that there's any OOB structure that exists beyond temporarily assigning units to a battle plan and sticking a general on top, so I'm guessing this would need to be done.
You'd need the ability to assign batallions to a corps, at least in an administrative sense. They wouldn't strictly need to be represented on the map as individual units, they could either be attached to a division or simply reserved in a separate pool (off-map). The main difference between this and just changing division templates on the fly as I suggested above is that the corps asset could keep any gained experience even when not assigned (and you're not going to accidentally use that equipment for a new constructed division or replacements).
You'd need to be able to dynamically assign (and re-assign) assets to a division, without needing a new template all the time. Being able to unlock a "corps asset slot" (or more than one) on a division template, which could be assigned a variety of battalions but is not "populated" when such a division is constructed, would be sufficient. Reassigning a corps asset would probably require some kind of time delay proportional to the travelling time between the two divisions.
You'd need to spend some extra unit design/balance/tuning time considering possible combinations of corps assets so that there aren't any "broken" combinations.
Finally, you would need an AI that was capable of making good use of such a mechanism. If the AI can't use it effectively, it just makes the AI that much worse compared to a human player.