I'll be short and to the point. For now, I have not encountered a HEROIC mission that absolutely needed a tank specced tank (TsT) or a heal specced healer (HsH). Off-tanks and off-healers can carry those roles fine in these types of missions. The problem I'm seeing is that people don't know how to correctly deal with large groups of elite and semi-elite mobs. Most people think: "cc the weaker one's, we can deal with those later'" THIS IS VERY WRONG!!! The correct way to take down a group of mobs, even without a TsT and HsH is this: Picture a mob group of 3-4 yellow star elites (strongs) and 2-3 silver star elites (weaks). 1) cc as many strongs as the group can...NOT THE WEAKS!!! 2) tank the remaining non cc'd strongs...DO NOT DPS YET!!! 3) burn down the weaks...DO IT FAST!!! 4) burn down the tanked strong NOW! 5) burn down the rest of the strongs, re-cc'ing as necessary. This quickly eliminates the threat of 2-3 weak mobs that may be killing your healer or inflicting unneccesary damage on the non-specced tank (or anyone else) and allows the non-speecced healer to better focus his/her heals on the tank who is supposed to be taking most the damage. I understand this may not work in 100% of the situations but it should be grafted into everyones playstyle as the go-to strategy for most mob groups in HEROIC missions and even some trash in Flashpoints. In fact, even with TsT and HsH, this is still the best strategy to bring down mob groups.