Cool, Pinot, nice work. It is fun to see how other people do these instances.

You do Garfrost quite a bit differently than I do. I have all my guys stand a bit in front of the bottom of the stairs, almost on the edge of the pit. I then pull Garfrost to the middle of the stairs with my tank, making sure to consecrate to pick up the adds. You can strafe or move forward on your slaves if they get the rock thrown at them. Then when Garfrost runs back to his forge I just stay there - the frost debuff automatically wears off as he runs to get another weapon. Repeat till he is dead. This ends up being less movement overall as you avoid hiding behind the thrown rocks.

Might try that as an alternative and see if you like it.