Ok, so for those of you not sure what I'm talking about these are the weapons in question:
https://ptr.wowdb.com/items/172200-skshuul-vaz
https://ptr.wowdb.com/items/172187-devastations-hour
So I just sat down with my current stats on a heroic geared warrior to try and determine whether I'd want the axe, the sword or one of each.
Stat-wise the sword wins. Haste/Crit > Haste/Mastery, but that's not the fun bit. The fun bit is if they roll corrupted and you get the fancy procs.
So under my current stats I'd expect an extra 20k hit twice a minute with the sword. So probably an extra 80k damage each minute while dual wielding under the assumption there's not a weird shared CD. This damage is a big AoE cone in front of you - probably the same as DH eyebeam or the azerite beam using focusing iris.
Now the ax explodes for 300% of your armor every 30s in combat. Under my current stats it's also about 20k. So - again provided no weird CDs stopping things from overlapping and requiring you to say equip a trash weapon for 10s in the fight and then put the axe in your OH - you'd expect again an extra 80k of damage each minute in combat.
The ax does the damage in an AoE around you though.
So in my opinion the ax is going to be the superior pick despite having less desirable secondary stats since it can help with things that aren't in cleave range - which on the last two fights especially are going to be pretty common.
That said, the ax has the potential to be an utter nightmare in Tol Dagor.