Although I've promised an extensive review of D&Dg, I don't have the book on hand while I have Web access (at work), so I'll post impressions of the book, supplemented with some thoughts and opinions about the book (its utility, etc.).
3rd Ed. Deities and Demigods provides full stats and role-playing information for numerous deities. Rather than compressing the deity entries to a minimum (thereby allowing for more deities/pantheons), WOTC has wisely chosen to set a good precedent by extensively detailing those deities that have been included. It sets a good precedent, IMO, because the 1st Ed. book focused on deity stats and the 2nd Ed. book neglected deity powers and abilities in favor of descriptive text that could just as easily have been extracted from a mythology text at your local library (we have several). Whereas deity stats require much more work, and fortunately have been provided in abundance.
As a perusal of the Web Enhancement will convey, D&Dg does not provide much detail on a deity's church or followers. However, I do not perceive this to be a drawback. Each campaign is unique, and campaigns likely to use one (or more) of the pantheons therein will tailor those deities and their faiths to their individual milieu. The functional aspect of divinely bestowed powers in 3rd Ed. is no where near as abysmal as 2nd Ed. (with its god-awful Spheres and unbalanced Granted Powers) and yet more colorful and flavored than 1st Ed.
Many questions have been raised regarding the utility of deity stats. Aside from the conventional argument concerning the possibility that the said information may be used in a campaign that focuses on high level play, the stats in D&Dg provide information and ideas, in and of themselves, that could not be conveyed otherwise without exhaustive descriptive text. A careful DM will take the time to note that one deity has a higher Int and/or Wis than another (and possibly rival or enemy) deity. These facts can help to establish relations among worshippers and the coorelation of those deities' forces.
Arguments have been advanced stating that statted deities are "reduced" to stat blocks. Blah. 2nd Ed. "reduced" every single deity of every real-world pantheon to nothing more than a power level, utterly ignoring the very carefully established differences among deities within pantheons, distinctions that might have taken hundreds or thousands of years to establish. And while statting deities may ignore/overlook some essential aspects of deities, it at least approximates further inequalities that actually existed among deities in mythology and (with 3rd Ed.'s approach) without reducing every deity to a rigidly defined power level. Of course, such power levels exist (greater, intermediate, etc.), but these, in the end, do not define a deity in its entirety.
Quantifying deity attributes, therefore, can be construed as an outgrowth of the need to 1) provide option, 2) to provide information simply by virtue of the existence of a particular attribute or power and 3) quantify deities to allow for the closest approximation to real-world mythology. In 2 above it becomes an alternative to extended descriptive text, and in some ways is more informative. Knowing that Zeus occasionally manifests to seduce women is made all the more interesting via a knowledge of his Charisma score of 29 (which I thought could have been higher). Not only that, assuming a campaign based on Greek culture and mythology, we have an attribute to actually determine the likelihood of success in such an endeavor, rather than simply (and FALSELY) assuming, "Well, he's a god! He simply succeeds." Using the logic (?) of 2nd Ed., of course thats the case.
