If you gotta' move, just move. The important thing to keep in mind is that most DPS know of the annoying AoE monsters and that will be their primary concern in order to remove annoyance. It's also good to remember that while these AoE monsters are casting they won't move, which allows you, yourself, to take back your original position when they complete the cast. As long as you do this, the important enemy to kill won't move and thus allow DPS to still complete their positional skills.

As you become a more experienced tank you will also be able to recognize when moving other enemies will benefit the DPS most. As an example, let's assume you're flanked on the sides with an enemy also at your front that are only melee enemies. The DPS ideally will focus one of them down and in order to minimize DPS movement you can use the time just before it dies to preposition the other two enemies. Basically, always keep the backs of your enemies facing the party.