Almost every single class in WoW has one or more resources they have manage in order to optimize DPS. Retris have Holy Power, Wars have rage, Rogues and feral have combo points and energy, DK have runes and runic power, Shadow Priests have shadow orbs, most casters have to watch there mana now, especially Arcane mage, Balance druids have eclipse, etc. Enhancement shaman have none. Our mana never runs out ,our spells cost next to nothing and we don't have any other mechanics to watch for. I'm not saying that i dont like the fact that we no longer have to worry about mana, it's just that i don't quite understand why?
Retribution paladins are very similar to us, they have very small mana pools, spells are very cheep and there mana regen mechanic makes sure they never run out.I remember a Q&A at BlizzCon, when the guys from Blizz where asked why did Paladins receive Holy Power and they answered : we feel that Paladins need a resource to manage. So the question is: why not enhancement to?