[Update #2]: The beta update has now been released in full, though sadly without the Huntsman rework.
[Update]: The Big Balance Beta has now also brought in a rework to the Huntsman career.
Ever since the Winds of Magic expansion and the accompanying stagger changes, the balance of weapons and talents in Vermintide 2 has bit a bit of a mess. For pretty much every single character and playstyle there were clear-cut choices that were superior in nearly every way, while some of the worst weapons were so terrible that even diehard fans didn't bother using them in higher difficulties.
All of this will soon come to an end, however, as Fatshark has teamed up with a group of talented modders in order to do a comprehensive Big Balance Beta update. While it doesn't change every single weapon and talent, the beta has significantly improved the almost-invisible weapons like Kerillian two-handed sword or one-handed sword, as well as nerfed the overpowered ones like dual daggers or sword and dagger combo.
If you're curious about all of the details, you'll find the full list of changes over at the official forums. Most of the tweaks also have comments from both the modders and Fatshark themselves, so if you're even remotely serious about Vermintide 2, I'd highly recommend going through them.
On the other hand, if you prefer to simply dive in there and see how everything works out in action, you'll be glad to hear that joining the beta is a remarkably easy process. All you have to do is navigate to Vermintide 2 in your Steam Library, go into properties and then betas, and from there select the "balance_beta_summer_2020" update. As soon as you've done that the beta should begin to download, but if it doesn't, simply restart Steam and you should be good.
Have fun with the beta, and if you have any sort of feedback, make sure to sent it to Fatshark.