You need berserk only for hex.
For all other matchups, or wd without hex, you can play without berserk. Chain cc builds will heal you through juggernaut.
Look up some streams of top barbs, they beat all classes easily, without any cc breaker skills. If people are attempting to do perma stun, it relies on very fast attacks with chance to stun, it heals barb so fast, that strategy just doesn't work, because you can't kill a barb then.
Hex behaves differently because it stuns you for longer period of time, with 100% accuracy. So you will not heal rapidly, like for example if dh attacks you with series of stunning attacks. And then wd is free to just dps perma pig barb to death.
For pvp against barb to be fair, wotb should be banned, and hex should be banned at its current state. Then if is fairly balanced.
Lol current PvP for barbs is either you WoTB or you counter-pick.
You decide which is cheaper.