Is there a more logical balance? How do you balance group vs group? You cant put same classes with same gear/AA in each group so 1vs1 balance pretty much balances everything.
Nowadays most barbs who gets kills in minis uses the decap/atg setup (with insane gear alongside) which was called nab playstyle back in the day. A player who does good without playing like this is too rare. Either double ended zerker tree with atg or reaver heavy hybrid builds work but some barbs(me included) wants old classic zerker spec(without decap) to be viable again and it wont be until 2 handed combos are buffed. Barb's two handed damage against heavy/plate armor is a joke atm, simply there isnt enough damage vs survivability overall.
There is only one barb I know who does very good on every spec/playstyle he plays(he doesnt play with decap nor heavy reaver DoD spec) but you cant rely on that reference to balance da BARB!