Because if s/he did not have the shield and got the same crit, then the arm is broken or severed (ouch). If shield is present, then the shield is broken and no longer provides the additional DB and the arm would only be bruised (oof).
Except if he "did not have the shield", he may not have had the same crit (nor the same damage) than if he had one. In other words, a shield already makes a difference. Making it doing so again through a situational crit is redundant. Either don't make it add DB and use situation crit, or make it add DB and don't have situation crit, not both.
I agree wholeheartedly. However, considering the randomness of dice rolls, he could get that same exact crit either way. Thus, the reason some crits need the "if has [this], then [this] happens, else [this] happens."
Would you like such a crit to say your arm is broken although you had a shield to deflect the blow? Yes, sometimes the blow can be so powerful that the shield blocks the blow, but the arm is still broken. Good example is Eowyn's fight with the Witch King. His flail blow was so powerful that it shattered her shield
AND broke her arm.
But what if the blow is not that powerful? Just strong enough that a shield could deflect it enough and leave the intact? Maybe, smarting with pain? Thus, the crit result would be shield is broken.
Again, also remember that the crit descriptions are guidelines on how the results of the critical injury
can happen, not how they
do happen. Ultimately, it is up to the specific GM on how to interpret how a critical actually happens.
However, I still agree wholeheartedly with having the "if...elseif...else" situational crits.
rmfr
