Bullshit. As has been expressed many times in this and other threads, the benefit was primarily around the devs being too lazy to fix the pet AI.
Yeah, why would a guy who uses ranged weapons focus on them when he can roar and whistle at Fluffy while spazzing around the room?Marksmanship has never fit the class identity of hunters anyway.
In the pre-Cata design, your three trees represented different aspects of being a hunter. Cata decided that each tree was a separate class itself. For example, newly dubbed Fire Mages suddenly forgot all the frost and arcane magic they'd been using for 80 levels. Same for hunters, no longer were we sharpshooters with wild beast companions, and traps and poisons.