atm they are all specced balance, whilst levelling I have yet to run into mana issues.. most mobs die after 5x Starfire (or i'll pull the whole area with 5x starfall and then finish of the survivors with Typhoon).
Running the Nessingway Quests in Nagrand, I completed the whole quest line from start to finnish without taking a drink. don't get me wrong I have to take a drink with them occasionally, but it's quite a infrequent.

Quest Bosses take the onslaught of 15 trees, Insect Swarm and spammed Starfire or Wrath (boss fights normally last 15-20 seconds for a 30-60k boss).

For instance runs I have one dual Specced with resto and one with Feral.. no issues so far (but I have only run BF, Ramps and Slave pens :P ).
the only real problem I ran into was the Blue Brothers on the Ring of Blood quest, trying to get my macros set right for that one.