Disclaimer: Haven't down this yet.
Some notes from limited attempts thus far...
1) When you down the Crossbowman, contrary to what the guide implies, you are not 'sent' back to the main platform, there is a small yellow glowing orb in the middle of the corpse which you must right-click to then be sent back.
2) Personal opinion regarding the double-tap fears from the crossbowman. His arrow-spray is sporadic and unpredictable, making dodging nearly impossible (unless someone's found a way I couldnt think of). Dispelling is posssibly not worth it, since the fear has such short duration. I heal for my group and stopped bothering to dispel after the 4th attempt, finding myself more than preoccupied with healing and collecting orbs. I do however recommend Tremor Totems and Fear Wards, very useful.
3) Regarding Dread Blossom, the guide isnt joking, this hits like a truck. However, since DPS on these platforms is sensitive and getting back fast is good (getting back before the next Ominous Cackle is pretty much mandatory), I strongly recommend all raiders with non-stasis immunities to save them/plan them for this ability to boost overall DPS. Hand of Protection is also very helpful, so pallies with clemency can help out squishies. With care and planning healers CAN heal through this ability, but a misstep can be very costly so I think LoSing as the guide recommends is wise for players who have no CD.
4) Overall impression of the encounter is that the better you do on the Crossbowman's platform, the simpler the rest of the fight becomes. So spreading out to collect orbs, minimizing fears with whatever you can, ensuring no deaths to Death Blossom, and maxing your DPS via whatever means you have.
Thanks for the guide! Will follow up with any further thoughts once we get this down