I have been around for 2 seasons now (S11 & S12 the current season). Prior to that I was a beta tester for D3 way back in the day and main Wizard back then; the glory days of doing the campaign mode over and over at level 60 and getting Rek by off screen mobs that had so much HP and Damage that I just flat out quit the game as the difficulty was not there; it was just not a fair and balance game. Years later I came back and played Season 11 WD and loved the game again. This season I went Crusader for the Hammerdin as I thought it would be good; oh boy was that a mistake (hammerdin I say as the best build in solo is Condemned Crusader at this point of S12). So I went back to WD and I got a Solo GR 75 pretty easy with 1 ancient gear with Zunimassa because the pet buff to the 6 pc was huge. But WD has the same issue as the Crusader IMO which is the lack of instant travel.
What is instant travel? Barbarians have a Charge, DH have Vault, Wizards have Teleport, Necros have some dash thing, Monks have their dash click travel. The Crusader and WD have the run to every location; at least the WD can spirit walk out of a wall from a Waller mob.
So why am I saying it is arguably sound to say everyone should run DH? It does not take much to gear up a class; today it took me 6 hours to fully gear the last pieces of my DH to just do T13 speed runs. Once I get ancient gear on it, I will progress into the GR80-90 speed runs for better gear and gem upgrades.
Why DH works so well? I mention the instant travel; well DH like to run the UE mode which is a really fast run speed. I am sure other classes like Wizard can do this as well. However, the DH reduces the chance of death by spamming Multishot or use the Marauder set and spam grenades; which I have not done yet in S12 as UE Multishot is king of the crops right now and easy to gear for in regards to items.
So realistically, if everyone ran a UE Mutlishot next season, you could have a entire T13 farm team that would reap the Death Breaths (DB), which could build into things like an easy primal ancient Karleis Point for the Imaple build.
Speed builds are also best for GR 80-90.