It's a good thing that you mentionned A1S and Royal Fount. Look at this :
http://i.imgur.com/Csnxu1p.png
These are the precise timers for every single attack and mechanic for the entire fight. Even Royal Fount is in there. ALL damage are completely scripted. For example, I have the same thing for A3S :
http://i.imgur.com/EJXEalr.png
And it has been the case for all raid fights since the beginning of ARR.
With enough experience you can see the fight in advance like with Sharingans because of that. Combine that to the fact that damage are low enough to be completely survivable in DPS stance, and that tank busters are even weaker than what they were before 3.0 (look at T13 pre-echo, you'd never want the MT to be in DPS stance in that fight, not only for Flatten, but also for Flare Breaths + auto-attacks which were threatening enough).
Edit : I want to add that these images were not made by me, I found them, but kudos to the crazy guy who took the time to do this.
