Hello,
I have yet to test this out on Ravana EX, but it would seem the Blizz 3 allows for an extension/breathing room into our casting rotation, when I don't use Blizz 3 my timers seem to die off faster not netting more time to finish casts on my other spells or I'm too close to the timer dropping off, making everything clunky. This is the best description I can honestly give. Here is the a vid I also chased down on BLM rotation, which is similar to Reddits. However, Reddits used to use Blizz 3 in his starting opener but has since taken it out. I guess it will just determine which rotation is best for the battle.

BLM Rotation Alternative:
https://www.youtube.com/watch?v=wVhXpAU3-GI