Oh yes I agree that it's a good idea to communicate, encourage and give advice. But, at the same time, if the tank has stopped with a small pull, and there are enemies nearby that the healer can easily add to the group without causing any threat to anyone, I don't see any harm in it. On the contrary, I would view it as good team work (yes, even if I would be the one tanking).
Then it's another matter, in my opinion, if the healer (or anyone else) is sprinting ahead of the tank and making the pulls in the first place.
Apart from some leveling dungeon pulls, the incoming damage from 1 group of monsters is negligible and doesn't require any management from the tank nor the healer in dungeons (and, additionally, resource-wise - meaning cooldowns, MP, and TP - it is generally also more effective to pull larger groups of enemies than small ones). I would also argue that dodging AoEs while pulling and tanking is something you should learn way before you encounter a situation in which your group wishes you to pull more than one group at a time. Or at least I was thinking of level 50 and up dungeons writing my reply, not Sastasha.
