Personaly i dont use auto calc,
Becous I like the battles, So i cant say iv ever noticed anything wrong with it,

And if the state of auto calc Right now means You either do it your self Or dont do as well, then id say Keep it like it is,
Becous even with a large army if you have no skill You could loose,
But the auto calc may just say you won,
And newbie players would be compelled to use auto calc Instead of actualy Playing the game.