I finished Caverns of Thrumfall in t2 with minstel and hunter and I had a lot of fun. Currently the best new instance for me.
If traited blue, on the way to bosses one can use CC, debuffs and bear in great use. In half the cases the minstel didn´t even need really to heal.
I tanked the first 2 bosses with the bear. With help of our debuffs it makes easy for minsrel to keep everyone alive.
When fighting the second boss, the group needs to stand on the wall to mitigate kicks. We spawned the drakelings only on the begining of the fight, defeated them and then it was only about aggro management between the hunter and bear. One needs to hold SI permamently on the bear, otherwise the boss will attack someone else.
The last boss is ... complicated if one wants to understand every little detail. I am not sure if I should write about it to avoid spoiling it. It required very specific strategy from LM point of you. If wished, I can explain it in detail.
In the end, you are right, there is so much aoe damage that LM can´t heal it by himself. And there is insane fire and frost mitigation, so LM can´t do damage there. But Lm can use its primary role: debuffing and CC. This way it makes possbile to return from this instance victorious.
Ich bin kein Deutscher, sorry für Grammatik.
English isn't my native language, sorry for mistakes.