Rogues do well, that is until they run into a critically immune foe, of which there are many, including the ever common undead and construct types. Yet it only makes partial sense, is precision damage not striking the enemy in weak points? While a zombie has no vital organs, it can still be crippled through a precise strike to certain parts of the frame. Even golems and plants have weak spots, even while lacking vitals. This rule replaces the normal critical immunity with the concept of critical resistance, a sort of required "damage reduction" which can be bypassed given the correct tools.