Only paladins have the threat reduction. It was actually intended as a nerf, so they couldn't tank by only healing themselves.

Shaman heals give 0.5 threat per point healed (basic healing threat).
I think paladin heals give 0.375 threat per point healed (25% innate reduction).

The reasoning for this is that paladin is a hybrid tank while shaman is not. Paladins AOE tanking through healing was overpowered in beta, in much the same way that using paladin as an aggro-pole on phase 1 Nef (when BoW gave threat) was very effective.

This says more about the state of paladin talents.

Paladin talents have always been compelte and utter trash. The last reasonable survey showed that less than 10% of all paladins have ANY 31 point talent. Simply put all the paladin talents are either sufficiently bad, or low in the talent tree they made no difference. Further there are only a very very few talents that impact our raiding ability, BoK, Holy power, Illumination. Thats pretty much every raid useful talent available to a paladin. And holy power would never be demanded by any reasonable raid. The running joke about paladins has always been the power of the 0/0/0 talent build because our talents are that unimportant. Paladins dont even have a choice of play style unlike every other class.

The reason paladins werent forced to spec one tree the same way druids were was because we didnt have a talent as good as innervate. Give paladins innervate as 31point protection and see how many guilds start demanding it.

Furhter, Caydiem was through and through a druid. No offence, but she clearly had a biased view of class balance which could be seen time and time again in her forum posts. She was defiantely "pro druid", the question isnt wether you had a CM "onside" but how much influence she had. Now given that she explicitly told the paladins that she couldnt actually answer any of the Dev questions in their meetiing for the paladin patch, nor justify any of the player sugestions because of her lack of experience in playing the class, Id say that the druid review is at least in part due to having Caydiem play a druid. Even if it was only that she could given much clearer and better reasoned feedback to the Devs.

Judia

Th numbers were tested and posted in the US forums, however the post itself is pretty much lost. There was a very significant threat increase on paladin healing threat during the 1.9 patch, as a number of paladins reported pulling aggro and aggro issues on a large number of encounters where previous experience had shown none.

Caydiem did post saying paladins were designed to have low threat heals to make them better heals. Again the post is probably lost to the depths of Blizzards forums, but it was posted in blue and upset quite a few paladins who remebered being told the nerf was to stop us heal-tanking.

Im not sure which of the above points warrented being redirected to the official forums. I certainly found it infuriating to not only to see a blue post an untruth, but it was at a time where the increased the threat on our heals without putting it in the patch notes.