Paul, it looks really flavorful. I love all the different options and array of powers. If I'm understanding your rules correctly:

- Any character can acquire Initiate powers of any god for a day by sacrificing 1 point of characteristic for the day, at a temple

- A devoted character always has Initiate powers of his god, and can gain Devoted powers of his god by sacrificing 1 point of characteristic for the day, at a temple

- Blade dancers suffer much narrower weapon choices but gain a Gift, and can also gain the Blessing in lieu of an Initiate power

- Priestesses get a Gift (bonus power on top of ACKS class powers)

- Mystics get bonus class powers at 3rd and 7th level, on top of their ACKS class powers, based on their order

- Mages get a bonus class power on top of their ACKS class powers, based on their order

So it seems like you're giving an overall increase in power to all these classes (and it looks like you plan to do the same for the other classes) in exchange for restrictions on behavior, tithes, etc.

The only thing that jumps out at me is that sometimes the Sacrificed characteristic and the power granted work at cross-purposes. This could result in wierd break points - for instance, an archer with 17 DEX is going to be much more likely to take advantage of Apollo's gifts than an archer with 18 DEX.

I might recommend switching the Sacrifice to a characterstic that doesn't interact with the power (for instance, may Herakles calls for a sacrifice of Wisdom) or perhaps having the sacrifice be 1d3-1 points.

For instance, at 16, rolling 1d3-1, you'd have a 33% chance of staying at 16 keeping your +2, and a 66% chance of dropping to +1 (15 or 14). Expected bonus is (.33 x 2) + (.66 x 1) = 1.33.

At 17, rolling 1d3-1, you'd have a 33% chance of staying at 17 and +2, a 33% chance of dropping to 16 and +2, and a 33% chance of dropping to 15 and +1. Expected bonus is (.66 x 2) + (.33 x 1) = 1.66.

At 18, rolling 1d3-1, you'd have a 33% chance of staying at 18 keeping your +3, and a 66% chance of dropping to +2 (16 or 17). Expected bonus is (.33 x 3) + (.66 x 2) = 2.33