As i mentioned in the latter part of the raid, picking up those adds in P1 is horrible, people are spread over the entire platform meaning i do nothing but run in circles like a headless chicken the whole time attempting to agro them.
We are covering a space twice the size of that in the video by using the larger platform; on top of that the first wave has already reached the raid as we tank swap meaning there half dead by the time i reach them and getting agro is nearly impossible, which is what was almost killing Illiath every pull.
Not sure what else we can do about it other than group up more, and not position yourself on the opposite side of the mass of pools to the tanks.
Starting on the larger platform should negate the need to move, in the video there using the smaller ones; the raid was really only hovering around the left side of it leaving half clear.