Nah, it was hyperbole, the real solution is to give synergy in Frost abilities, plus an AoE Runic Power spender.
BoS is every 2min and the CD doesn’t start on cast but when the effect is done, so even if you manage to keep it up for a minute, after it ends, you’ll have to wait another 2min to start, while Unholy has DnD super spread dmg every 20s (30CD but lasts 10s)
How’s that Frost Scythe has 5 target limit but DnD scourge strike has none? Pandemic spreads to all, like Frost Fever, but you can’t expunge/epidemic the frost fever, just use a single target Frost Strike for laughable dmg in aoe, or run the weak talent Glacial Advance, that also is in a line rather than a cone or cicle (less spread, harder to hit all mobs) and has CD.
An easy solution is to make Frost Scythe actually do more damage in AoE (it does less than 1/5th of an Obliterate damage, so you don’t really do any more damage in aoe using it over Obli, actually, doing less since obli cleaves to 1+ in DnD while Frost Scythe does nothing; only during Killing Machine and Inexorable Assault you get a nice dip of dmg, still far from Unholy effortless Epidemic spam)
Or make BoS baseline like the FrostWyrm and turn Frost strike into a 20-40 runic power spender (currently at 25 is super akward, it’s equivalent to 1 obli and random runic power gain from Fever, but has diminishing effects on multiple targets) that, when using 40 RP, does cleave damage to targets afflicted by Frost Fever in 8y radius or smt.
@Slimefinger And… you must be dueling bad Unholy, bc Frost rly has pathetic dmg. Festering Strike does the same dmg as Obliterate with 2H weapon (even with the supposed 30% damage boost of using a 2H, it’s the same as Festering) but doesn’t apply fever, while Festering puts the bursting sores. AoE?
Only breathe which is a talent, and very ocasional (unlike Epidemic)
Currently I am Unholy with 1 hand, yes, the 1 hand from back when I played Frost, and guess what? I’m doing way more damage than before. Sure the wyrm is a spike of dmg that can only be matched with Army of the Death, but outside of that 3min CD, you really can’t compare the damage meters. And both have the same utility (Unholy has stun with the Gnaw and Dark Transformation, Frost has nothing).
Check the charts for raid and Mythic+, in any percentile, always, Unholy DK is way, way better than Frost even after nerf.
On a funny note, your DK base abilities: sacrificial pact, death coil, and Death and Decay, all do Shadow damage, so it’s better for Unholy Mastery 
as if they needed more, right? Frost really sucks, it is fun, but sucks.
And if you want real infinite breathe, go to Revendreth and drink the Overflowing Chalice. If you activate breathe and have +16 Runic Power for when it ends, you’ll keep spewing frost forever, considering you don’t go below 16 RP (it no longer costs any Runic Power, but once you cross the 16 mark, it goes away). Just every minute or so, hit a mob with obliterate to get 100RP. If you have the PVP talent Infusion, you can keep it up 100% with DnD, infusion and empowerment.