We cc 1*trapper,1*blademaster,2*mender
Burn down/cleave/multidot trappers first, before they die take away the cc of the remaining blademaster.
Blademaster should die pretty fast after the trappers. Menders last, they should be down to like 30-40% by now. Kill them.
Boss shouldnt be nuked more than down to ~80% if adds are still alive.
Dodge his blade whirl and the windbombs, stack for his ae dmg.
We only cc'd 3 targets. One of each grp and then burned them down evenly. One melee on each mender for interupts and the raid ready to interupt if one of them would be trapped at a bad moment. 3 healed, 1 tanked it. Work out great for us.
Your setup is great for aoe'ing so dps shouldnt be an issue.
We burn the mender as quickly as we can. This allows 2 people to not have to worry about their CC anymore. Then we bomb and cleave the rest so they drop simultaneously.
The whirling blade is probably the most deadly mechanic in this encounter. Emphasize to your raid members that they need to dodge it. The boss will make an emote and turn towards the direction that he's hurling the blade at. People need to dodge it when he throws it and stay away from there until it has made its way back. That's what ruined a decent amount of tries for us. So avoid stuff that you can avoid. It's already enough that sometimes the blademasters will decide to randomly oneshot someone (there's been weird stuff like 3 charges of 168k each happening to the same person even though one of the blademasters was peacefully speared away in the distance. That log left us scratching our heads, shrugging and doing another pull).
When I did it we CC'd 2 trappers, 1 mender and blade master. With our strategy and set up, we decided that trappers were the most annoying, which is why we picked 2 of those. We used 1 tank, 3 healers and 6 dps (healers felt very comfortable, there was discussion of dropping to two). We just assigned interrupts to each mender and aoe'd everything with the aim of having all adds die at the same time. The trapper was the main focus of the damage since he was the only one of his group, but target switches were made if one group looked high ofc. No increased boss damage while adds were up, no worries about who was cc'ing what after one group dies or having 3 of the same add out at the end or anything else, just full out aoe.
2nd phase is just avoid bombs, keep the raid behind the boss and loosely spread, and stack up for blades which may need cds to help get through the damage. The boomerang hurts a lot too in this phase, at the very least don't allow it to hit you twice. Move the boss when bombs get too clustered up and it should be a kill.