First I’d point out that fighters got this same treatment with weapon proficiency, on what is supposed to be a much more exclusive class ability, imo. I don’t know that barbs necessarily have any intrinsic right to exclusivity on ambidexterity. It always has been an ability everyone can have. On a side note, barbs also get the most out of the ravenous appetite skill—it’s clearly one made with them in mind.
However, if there’s going to be a new barb askill, I’ve been a fan for a long time of the “using 2 2hd weps as 1hd” idea.
Also, as Anon pointed out, it’s not like all classes now get ambi. Enough xp to max two-weapon, you’re talking about maybe the top 20 players on the alist? By the time a cleric on there has maxxed two-weapon, your barb could max natural armor and ravenous apetite, and their “ambi” still isn’t as good as yours.