Do you control the arty much yourself when you do this, Dave? Just asking as I always find much higher arty casualties if I control some of it myself to any substantial extent. That might be a different point - how effective is the AI at bringing in arty fire? Quite often I take control because I can't see anything happening to break up attacks, clear objective rings etc. I used to think it would be 'most realistic' if I let the AI control all my arty, but, frankly, I now find it difficult to draw most scenarios if I do that.
The enemy arty is a bane in this gamne, because it's so effective. But that's obviously the way it was in real life, if you even read the stats for percentages killed. I wouldn't want it any differently. A drop from 70 to 28 seems a lot, though, as you imply, depends what happened in the actual fight.
Less routing more retreating sounds like it will make a lot of us happier - until we notice the enemy, surrounded, outgunned and hanging on, retreating a few hundred yards, coming back at it after a pause, again and again...never dying... etc.....I'm sure you can't win, Dave.
Looking forward to this new build. :)