That's not the point OmniJackal. Stack spawning is not only annoying but also beats the crap out of any immersion and sense of accomplishment you get for correct planning and winning. If you win a major battle, it should mean something. And if AI can just spawn another army out of thin air, then victories don't mean squat.
Personally, I played Date on Legendary (which sould be same as VH/VH afaik) and on the first few plays I got steamrolled by the Mori(?) because I kept running into new armies with my counterattacks and getting pwned before reaching their castles.
After this mod was installed I noticed this doesn't happen anymore. The AI is still very challenging and can spawn units pretty quickly, but there are no magic armies appearing out of nowhere anymore. Now when I win a major engagement, I know the enemy is weakened and there is real opportunity for a counter-attack.
So thumbs up for this mod, saved the game for me!