It will matter when Helltooths raw output on 15 targets dropped from 120tril dps to 50+ tril depending on number of elites because you are back to furnace.
What they need to do is lower garg (esp cold rune unless it doesn't work the way it reads) so that they can boost the sets in general (if they're not going to bother actually fixing them)
Honestly this change won't make much difference to anything except super high GRs anyway, but everyone jumping on the wd bandwagon will probably get right off it after this.
Pure single target rift guardian it went from 19 tril on a very high tier boss to 14 tril.
Meanwhile gen monk is doing 80tril in 15 target aoe(uneffected by amount of elites just targets are more area dmg) and 23.3 tril on boss.