I have been leveling WHM lately and also learning scholar (I already had summoner to a fair high level so it was a matter of backtracking for class quests and gearing). The VAST majority of the dungeons I have done as a healer have not been bad. I have had new tanks who needed pointers on mechanics or took a few pulls to figure out how much worked for them. That is fine. I have never had a single pack pulling tank. I did have one that massively overpulled at the beginning of a dungeon and faceplanted despite my best efforts when I ended up out of MP (Quarn yeah too many bees and low DPS).

I will admit to letting one tank die semi intentionally. He would not put on tank stance, would not taunt, would only hit one mob in the pack and he was running off pulling way to much. By the third monster pull I was pretty much out of MP and patience (I had been asking him to put on tank stance multiple times). SO when he took off the next time the dps and I just sort of let him go. I didnt have the MP to heal him anyways at that point and by hanging back the MOBs didnt take us out. I rezzed him and we had a talk about tank stance and watching the healers MP. Dungeon went fine after that.

Probably was not my best moment but it worked out int he end.