Like was brought up earlier in the link to the japanese article about Enmity, there are two forms of Enmity. Volatile, which is reduced over time, and cumulative. Each are counted seperate of eachother, but kind of "added together" to calculate your total hate. Flash, stun, benediction, invincible and most other abilities are forms of volatile hate. However, what that page does not mmention is that most offensive spells such as elemental nukes seem to have both volatile and cumulative hate, in that the spell itself causes cumulative hate, but the damage from the nuke causes volatile hate. Although that's only from personal experience, and might be explained by the tanks sucking.
Both forms of hate have a cap. Thus, two paladins with different equipment can both keep the same amount of hate during a long fight, but the one with more enmity will reach it faster. Oce it is reached, you only need as much enmity that it will cap you out on each seperate list when you perform an action with the corresponding hate type.
Thus, to be the best PLD you can be, you need to try and keep both types of hates as high as possible.
While there is no clear facts, nor does the article mention it, that volatile and cumulative are stacked together at the end, it is the only way to explain why WHMes, which SHOULD get high amounts of cumulative hate during a long fight, does not pull hate. Which could be explained by there not being a hate cap. However, there has to be an hate cap, since towards the end of long fights, both PLD's, with different amount of +enmity, will have an equal amount of hate.
The third option is that + and - enmity reduce and increase the time at which hate is lost, and also how much is lost when getting hit. There is no doubt about the importance of getting hit as a WHM during long fights, but considering how rare it is for a WHM to actually pull hate, Enmity must work in strange ways.
Either way, I highly reccomend that you use MP refresh drinks pre-37 to keep your MP high, thus giving you more MP to cure others with. As mentioned earlier, Cure gives cumulative hate, which is not reduced as time goes by, but is only reduced by getting hit. Most hate tools you have (excpt for Provoke), is cumulative. So almost the only way to keep hate pre-37 is to keep your cumulative hate as high as possible. So invest in Enmity equipment to make your Cures give more hate, and cure others once they get hit by AoE's, since, if done right, they should not pull hate otherwise.