Going through the proposed Changes to unholy and not rushing head first into the topic angry has basically made me realize that Unholy in its current proposed changes needs 3-4 talents changed and its a Ranged Caster that could use an int based staff/trinkets.
Outbreak in its current form is not what is use to be, it just applies dots, One single Target, one self spreading. This can be done with scourge Strike.
Currently Scourge Strike spreads the plague and makes plagues Erupt. This is alot to put on one skill, but you could easily make it so Scourge Strike is a spamable that applies both Dread Plague(main target) and Virulent Plague(able to be spread and erupts , then turn Putrefy into a 15second CD spreader aswell as detonation (even if its a talent)
The only reason to currently be in melee range is for the Auto attack Runic Generation, So why not just bake that into Unholy and make it ranged? What i would actually propose here is Superstrain just 100% gives you 4runic power every time Dread Plague deals damage, atm its only a chance.
One of the only other problems i can see is Ranged interrupts, which you could just replace Outbreaks talent point with a 15-20yard increase(makes ranged interrupt 30-35yards) but 5 second CD increase (makes it 20seconds)
Not only would it make the class feel unique and special, But if there is no plans for a necromancer (in unholys current form i dont see a reason outside of necrotic healing, which could be done with a new spec tree for DK) you could have the ghoul army, Magic plate Disease caster, feeling like it actually does something Unique.
And dont get me wrong, i think it should strictly be Staff for int stats. Currently there is a million classes that have a million choices on weapons. Staff Drops in raids are basically dead loot for anyone that can use an offhand (all of them) and you want a crafted 1handed/offhand because of vault options. Sure, people roll on those items just because they dont have anything better but if it shows up in their vault vs a 1handed or offhand, the 1handed or offhand is usually taken.
You have proven it can be done with Devourer being Int Based but both Vengence and Havoc being Agi based.