You know, I always START with D&D. But I have to "fix" this or that, and end up with something that isn't quite D&D anymore.
Others have mentioned shifting the Prime Requisites around, so it's nothing new. But in setting details for my Fractured Ways campaign, I ended up doing it for three of the four "Sacred Four" human classes, with only Fighters staying with Strength.
As Friar Dave did, my Clerics have Charisma as their PR. Wisdom never seemed very well defined, and I always thought that, despite what they might say, the true goal of any Cleric is to gain new converts. That sounds like a Charisma requirement to me.
Not only does this give Charisma a clearer purpose to Clerics, it now makes sense to use the Adjustment (positive or negative) for the one unique ability Clerics have; Turning. So, in my Fractured Ways campaign, the CHA Adj. applies to both the 2d6 roll to affect the Undead, but also to the 2d6 roll to determine HD affected.
Wisdom? Given it's amibiguous nature and nebulous effect, has been dropped for now.