I reviewed Deus' data, and I need to toss in that it doesn't quite support the general conclusion that PIE is a useless stat. It does support that changing from 40 to 100 Piety against one particular creatures (Doblyns) has no effect. It also supports that rank is a very significant factor in the calculations.

My intuition is that creatures are built with stats and affinities just as players are. Some creatures have very high evade rates (Opos), some have very high defense (Coblyns, Crabs). Certain stat assignment will probably be more effective against some creatures then others.

Let me play devil's advocate here for a moment with removing the class rank from the picture, given the current system : what happens when a physical level 50 player starts off a new class at rank 1?

If stats become the dominant, and class rank is insignificant, those stats would allow the class rank 1 to be essentially as effective as rank 50, barring access to skills and gear. Such character in party play would completely dominate over lower physical level characters, diminishing their enjoyment (unless the goal is to powerlevel those character, letting them sit on the sidelines).

My intuition is that the class rank was brought in as the dominating factor in order to address this, but the side effects are significant. I think that any change to the way that stats work will have to go hand-in-hand with a change to the way that physical level works, and the way that points are assigned for classes of different ranks.