Its not that Battle Wizard is broken, its not too far off the other Characters… it does however have a significant advantage over Pyro due to how the things got changed around from the previous versions of the game.
After they removed Temp Health from accumulating in Ranged Combat it meant all the Sienna Characters could no longer gain Temp Health from using their Staves. So they ALL had to defend more.
Battle Wizard’s talents are all about Fast Charging the staves. While there are some that say you don’t need full charge to spam attacks… the BW will still charge even fast quick attacks to a higher level than either of the other two jobs.
What this means in the long run, is that Sienna jobs can no longer run around with their staff out 100% of the time like they used to or they’ll get crushed. This favors Battle Wizard playstyle as they can run with their guard up all the time, and quick swap to throw in more powerful Charged Staff attacks than either of the other two jobs.
They’re just faster and get more charge out of a Staff than either of the other two jobs.
Unchained is the reverse of this, they are unaffected by Overcharge so their weapon swings aren’t as slow and they can still melee effectively unlike the other two… ALSO…they’ve got a ton more defense and health so taking a few hits here and there doesn’t affect them the way it affects the other two. And they actually accumulate Temp health in melee unlike the other two.
Pyro ends up in the shoes of both not getting the melee temp health and not being able to charge staves as fast… so at a base level they tend to fall behind. They have to make up for that with Burning Head.