If its any consolation, my bad habit is not kiting as well and I clear almost all heroics (including Mgt) with 5 shamans. I hate kiting unless it's absolutely necessary as it slows things down a lot running around like a little school girl. The key is to build up your spell dmg, your AC and stamina will also be naturally higher if you have pvp gear too. Also pay particular attention to the mobs that will run at you and do the most dmg first / interrupt your casting, those are the ones that must be taken out first in most cases. Having a good idea how many casts and the sequence you need to do before you can switch off to another target to mow it down is important - you'll notice once your spelldmg and crit goes up that it takes less casts to plow a mob down making it that much quicker to take out 2 mobs before they even get near you. Also macro any spell dmg increasing trinkets into your lightning bolt or CL spam.

The first heroic I ever tried when hitting 70 was Mana Tombs and I got owned really bad. I remember thinking if heroics are this hard, how the hell am I gonna do this if I'm getting 1 or 2 shot to death. After much gearing and focusing on the right mobs first, and being able to switch targets during the cast to avoid the lag on the next cast I can confidently say it has become probably the easiest heroic that can be cleared easily in about 30-45 minutes doing all 4 bosses. Probably less, but I have this urge to kill things in there for the Etherum Prison keys and I like to watch the mobs pop like balloons when 5 chain lighting go off. lol.