Agreed, but the culprit of doomstack armies being too common is influence as well, mainly due to how easy it is to acquire and stockpile, even for the AI. If calling armies were made more expensive or the amount of influence available decreased (e. g. through making it finite), it should theoretically make armies scarcer.
Although this is a different subject and purely theoretical, I think that summoning and/or maintaining armies should also cost the army leader a significant amount of money (maybe something like 50% of the summoned parties' daily cost), so that having armies becomes risky and gold becomes valuable throughout the game.