But Alleo, that boils down to a management issue. First off, on the second boss, it doesn't matter if they stand on the electricity. It deals little to no damage to them. You can select the add, click on "engage" and they will burn it in a second. You scroll through the aggro list: Select - Engage. In the last boss, you can pretty much ignore the little flames. Their damage is pathetic. Just focus on the Sprite the same way you did it with the second boss: Click on sprite, engage. Then they automatically will go after the boss once the add is dead.
They get enhanced by a attack+defense buff. They shouldn't take that much damage from any source. If you're going as SCH, the fairy can pretty much carry that run. However, I agree with you on having more options for micromanagement.
I haven't experimented with GLD with a higher defensive stance. But I guess the aggro management will be better on GLA because it's a circular AoE, opposed to the wonky conal AoE combined with their weirdly programmed AI. Do they spam Circle of Scorn? I have noticed they don't seem to have skills on cd, as they sometimes spam it. (Barrage on ARC, for instance). I also noticed that, the higher the stance, they start using other skills like raid wide damage up. This is getting really interesting.
Side note: When you clear 10 dungeons with your squadron, you get an achievement and some workout emotes.