occam
Adventurer
So, no, this isn't technically limited to attack powers. Of course, this is hardly the most broken abuse of Divine Miracle. For example, an elf with Pray for More (Astral Weapon Utility 12) and a Vorpal Weapon can spam Elven Accuracy on each attack until a 20 is rolled, then switch to spamming Pray for More on the damage rolls until they have enough damage to kill whatever they attacked (since Vorpal lets you infinitely explode damage dice that roll max).
Pretty sure most DM's will disallow that one, but it works RAW.
Ouch. Seems Divine Miracle should at least be limited to once per round.