
Originally Posted by
Shurrikhan
Such is complicated, though, so let's try to contextualize this concretely lest it remain just nebulously theoretical.
Take a skill like Shadewalker.
So long as Enmity remained just a basic table that summed a product of total damage and healing and their respective modifiers, it was almost entirely bloat; its unique affordances were limited to add grabs for which a NIN's burst damage would outpace his fellows'. In all other cases, it simply, rather directly, became tank rDPS, supplied on CD. There was, for the party as a whole, no difference between your having Shadewalker or just having, say, 10 more potency on Gust Blade.
But that is true only for a narrow span of play in which most of its value would be wasted. Imagine, instead, for instance, a situation in which it'd make sense to place Shadewalker instead on, say, a sprinting Ranged DPS, for altogether more mitigation. That, too, would ultimately end up as rDPS, of a sorts, but so long as the use cases vary noticeably in their synergy, the skill's value, too, would vary greatly, with competing uses providing risk and reward: Do I simply use it on cooldown for this simpler <Affordance A>, or hold for this later opportunity for potentially far greater <Affordance B>?
Or, imagine if Ninja had actually built around use of Shadows. Now, Shadewalker is a more noticeable buff, sacrificing some resource on your part to give some further affordance to the target ally or affordance against a target enemy (which ought to be the rarer use case, as not to make it the default). You can now switch-teleport with the Shade you leave on the target, leaving a shadowy simulacrum in your place as you teleport behind the target. When using Dream Within a Dream, you and every Shade you've left now linear-AoE gap-close to the target of Dream Within a Dream. Etc., etc.
While you'd have only ultimately added a line of text to Shadewalker --"Attach a shadow of your martial soul to the target, transferring to them the benefit of Shadeskin if allied or converting that benefit to Shadows' Eyes if an enemy"-- you've expanded its use cases tremendously. And rather than needing, out of combat, to swap between which single capacity or set thereof you'd wish to eventually use, you'd have access to all of them. It'd just be up to you to learn which you can, in the given context, leverage best, in combination with the best choices among the rest of your kit.