I made similar thoughts, my conclusion was that the brayherd abilities are great when you want to put your focus on the theme and character of the army, I also made my own herdstone and will add trophies of crushed enemies To it
The Chaos abilities I would take for a more competitive focus. They give you some nice to-hit bonuses, which you need to get your bestigors, allied Bullgors etc. to hit in a reliable manner. Especially combined with the extra attack from the Batallion
As brayherd you won’t play defensively, so the herdstone will not help you in most of the battle rounds as all the goats will try to overwhelm the enemy at his front, flanks and back.