The Divine Storm fix is so easy it makes my brain hurt as to why blizzard doesn't do it. 3 easy steps:

1. Normalize Divine Storm with Fan of Knives - maybe this is what they are doing, but just tweak it so that when an equally geared ret and an equally geared assassin rogue hit DS/FoK, they do the same minimum, maximum, and average damage. Remove holy damage from it and make it just physical, so that it's normalized and you don't have to worry about inquisition and all that other crap just to make the damage viable.

2. Remove all cooldowns (except the gcd) on divine storm. (You might not like this, but it goes with #3). That means no shared cooldown, no cooldown on the storm.

3. Increase the mana cost of Divine Storm to 20% of base mana, or possibly even 30%.

The point of this would be to make it hit hard, be effective in any AoE situation, but you couldn't just spam it as you would run yourself OOM, and therefore would be forced to use mana regen from your judgement spell as well as divine plea if needed in your aoe "rotation." I like an AoE rotation of DS-Judgement of Righteousness-DS-DS-DS-Divine Plea-Judgement of Righteousness, something like that. AoE rotations are generally simple for most classes, and this would make it much more simple and much more effective.