You’re referring to the Lamentation belt. During the ptr, the belt originally gave a 200% damage multiplier to rend. However upon Blizzcon of that year, it was noticed and confirmed that the multiplier was to be removed from the belt which infuriated the Barbarian community. And once the actual patch itself rolled out, the damage multiplier was indeed removed which (understandly) sent the Barbarian community into a frenzy.
Afterward, I guess either Blizzard realized their mistake and/or wanted to appease the Barbarian community, but thankfully they brought back the damage multiplier for Lamentation (albeit at a weaker 100-150% instead of the original 150-200%).
So yes, that would be a rare example of them reversing a nerf almost immediately after it launched. However I wouldn’t count on that happening for Wizards in this case. The biggest reason I say that is because of the lack of communication we’ve received regarding this that explained their mindset when it came to major changes.
Ordinarily when they make heavy changes, they usually inform us of their reasoning (especially if the change causes a massive outcry within the community). For example the change to the Crusader’s Invoker set:
Thorns of The Invoker: 2-Piece bonus decreased from 350% to 90% and has a cap of 10 stacks. 6-piece bonus increased from 15,000% to 67,500% and increased attack speed bonus from 50% to 100%.
Developer’s Note: This is to address the Bombardment build that Crusaders have been tearing across the board. We’ve severely nerfed the 2-piece and compensated in the 6-piece. We also thought about extending the duration of the buff past 2 seconds, but we rather change a couple of things first rather than too many things to see how things play out.
This informed us of their reasoning of the change. Now as I haven’t touched my crusader for a long time, I have no idea if the change was effective and necessary, or if it was another example of using a hammer instead of a scalpel to fix an issue. However, based on what I’ve read from the crusader community, it seems a bit more of the latter.
With that said, with the exception of the Twisted Sword, we Wizards on the other hand had received nearly no such form communication nor reasoning for nearly all of the changes that we’ve gained in this patch, despite most of our community blatantly telling Blizzard that this change was awful. Even when the ptr notes were first shown well before the ptr itself launched, you had a great number of players try to tell Blizzard how bad these changes were, and yet it fell on deaf ears with no acknowledgement.
So yeah, I have zero expectations of them reversing any of these awful changes anytime soon. Not for this upcoming season, nor even the next.