Despite the lack of any random element, Divine Power is very random. You may sometimes get an extra attack, and sometimes a great boost to Strength. I did not notice any similar If-you-are-the-right-class-combination-and-if-you-have-the-right-strength-then-this-is-great-otherwise-you-are-out spell or effect.
Really, the half-orc Clr15 (Str 16, BAB +11) should have a similar benefit as a kobold Clr1/Sor14 (Str 6, BAB +7) using a scroll!
After reviewing the topic, I decided for all my campaigns:
- Ban Tenser's Transformation - not that problematic, though not worth the needed work.
- Ban Persistent Spell - similar problems: a fixed amount (24 h) instead of a bonus (double standard duration as Extend Spell). Some spells become really great, other are pathetic.
- Greater Magic Weapon is the 4th level spell of the War domain. Shout is the 4th level spell of the Orc domain.
- Finally, ban Divine Power. IMO, the spell as written doesn't belongs to 3rd edition. Even if I'd change the spell, it would end up as some kind of Aid-Bull's-Strength-Divine-Favor-Haste.