I can also say I've encountered this.
Now I'm no expert on hunter by any means but I believe the reason we use dire beast after Beastial Wrath is because it lowers its CD. I suspect that using dire beast before Beastial Wrath in the hope of a proc is a potential dps loss. I cannot confirm this but i suspect Azortharian will have tested this in order to come up with the recommended opener, trust my this guy knows his stuff.
Hope this helps a bit