There will be much more information about saints and their use, there will be 3.5 updates and substantially more material for the shaman and witch classes, including lots of new shaman/witch specific spells.
Signifigant new material for rangers, paladins and druids, including new true path feats which grow with the character as long as they stay true to their god.
And of course lots for clerics.
And that's just some of the crunch. All the major gods described in detail.
This should be one of the big 3.5 compatable divine caster books in the near future!
See ya,
Ken Shannon
MEG