I haven't really had an issue with this until the later dungeons, namely, Cutter's Cry last boss, Stone Vigil last boss, Dzemael Darkhold, and Aurum Vale. But I've noticed tanks lately have no concern where they tank the mobs, and it's getting on my nerves.
Cutter's Cry I've seen them tank Chimera almost on top of one of the ice patches, it lands far enough away that they are not touching it, so they are not inclined to move the mob. But as a MNK/DRG I struggle to DPS as the only safe spot is just barely enough side room, or the front.... or stand in the ice patch(which obviously won't work).
Same thing with Isgebind in The Stone Vigil.
Dzemael Darkhold, most tanks will pull the mobs just far enough into the blue area that they are standing right on the edge, with the mobs outside the blue area. Same thing with the Corrupted Crystals in there as well. And again with the yellow goop in The Aurum Vale.
Where is the common sense to see that if you have a MNK/DRG they are struggling to DPS without taking damage because you are tanking the mob in a very bad spot? A little courtesy goes a long way to making the run flow even smoother.
Also, what's with tanks lately wanting to play Merry-Go-Round with the mob? It's really annoying when the tank circles around the mob like 5-6 times where there isn't even a red area to dodge.