I agree, using my common sense of cross examining the functionality of skill, I'd rather have a new ability. If they would add something to ..."Guard" instead than just rising your shield, how about rising your shield and sword, countering with every block? Now that would be different, that would catch the enemy off guard and deal 25% more dmg.

Auto guard makes more sense and it give us the choice to up our blocking rate, that's what RPGs all about, choices.