Heroic Strike Versus Cleave
Raw threat values (*0.8 for battle/berz and *1,3 for Def (*1,45 with talent)).
Cleave has 130 threat untalented (this is split if you attack two mobs if on one mob the mob gets full threat).
HS rank 10 has 196 threat.
Scenario you use both on a boss (1 target so no threat split on Cleave)
Cleave is +70dmg and costs 20rage. (130+70=200threat///200/3,5=57,14)
70/20= 3,5dmg per rage
HS is +175dmg and 61,6 increased dmg vs Dazed targets.
HS costs 15rage (175+196=371///371/11,66=31,82)
175/15= 11,66dmg per rage!
3 Imp Cleave is +154dmg and 130 threat (154+130=284///284/7,7= 36,88)
154/20= 7,7 dmg per rage
3 Imp HS is 175dmg for 12rage
Same threat at 196.
-> I’m not going to calculate this since this talent only improves the threat/rage and rage/dmg but not threat/dmg like imp cleave.
Now lets say we do 6 Cleave for 120 rage and 420dmg (924 talented). That is 924 threat (1704 talented)
Now if I use HS to get equal damage:
420/175= 2,4 HS or 2,4*371=890,4
->Lets compare imp cleave vs normal HS
924/175= 5,28 HS or 5,28*371= 1958,88
As you can see just using fewer HS I get the SAME damage with LESS THREAT and it cost me less rage as well.
We see the breaking point is for Improved Cleave. Where doing relative same amount of damage Improved Cleave comes slightly ahead in doing less threat for relatively the same damage.
Even so using Imp Cleave over Heroic Strike on single target where you do not have unlimeted rage (aka as permanent 90+ rage) the threat ratio for dmg/rage is still in favor of Heroic Strike.