It doesn't take a Diablo 4 expert to look at all the weapons barbarians carry around and wonder what the other classes are doing only using one or two. Barbarians are Diablo 4's strongest class by far and it mostly comes down to the fact that, in a game about powerful items, they get to have four of the strongest ones at all times.
Despite what some players think, Blizzard is very aware of barbarians' inherent advantage and is going to try to lift every other class up to their level, starting in season 4.