blackjack: This spell assumes that each deity in a pantheon has similar goals/alignments. A drow god(ess) who is an enemy of the other elven gods would not count as part of their pantheon.

ericgrau: The bonus is either sacred or profane, so it does not stack with everything. Other concerns are reasonable. Prayer is 3rd level and has no material cost, so this should definitely be stronger than that. However, notice that for a vast majority of fights, it won't be giving a +4 to everyone. The cleric casting it will probably get a +4, but the other PCs will likely get only +1, or none at all. In fact, if this is cast by a chaotic good cleric, any lawful good allies take a -1 PENALTY.

Comparing to mass divine power (assuming that is 8th level), this is definitely worse. It should probably be more than 4th level though...

So let's say its 6th level? Then I should probably up the cost also.