From the PfH / Patch Notes, it looks like Larian isn't implementing any cost to Frenzy - no exhaustion after it's use. This makes the Berserker Barbarian much more powerful than RAW. Of course, BG3 gives away powerful BAs like Shove/potions/etc to everyone, which weakens the impact of a BA attack.
Berserkers also get an Enraged Throw BA while Frenzied. Which apparently knocks the target PRONE (does the enemy get a save?). The Barbarian doesn't really benefit from enemies being prone, what with reckless attack, but still that's another significant buff to the Berserker Barb.
