Blizzard has some new developments in how they wish consumable in-game items (such as potions) to be used and triggered with their cooldowns. Take a look:

We're actually in the process of re-evaluating the mechanics of consumable items in the game so that they work in a more intuitive manner. The goal during this evaluation as it applies to most non-equipable items with right-click abilities is to streamline them into an associated category. The outcome should allow an item of a particular category to only trigger the shared cooldown of all other items in the same category.

Specific details of this improvement will follow after we've concluded our design efforts.