God its ridiculous how much bad information gets spread around the forums by ppl who only think and dont really know what they are talking about.
Unfortunately, I believe this statement applies to yourself.
As aerial mentioned, Ias does help with cob. You might want to read this carefully:
what he said.
if you read nubtro's post, it clearly states and proves that IAS not only help you reach 1000% dmg faster, but you tick dmg faster.
Thus you can say that COB is directly correlated to your inventory dps in some sort of multiplicitave way after reaching 1000% dmg unlike 0-dogs which is more variable depending on your ias etc etc.
However, note that you will reach 1000% dmg about 1.3 seconds faster if you run 1.5aps vs 1.1 aps which is what people usually have with skorn.
You can safely say that if you attack an elite for 5 seconds with 1.5as vs 1.1as that you will be doing about 10-15% more dmg during that 5 seconds with 1.5as.
That is why i can still safely say that at the very end end game for the COB build at least, 1h+oh with high LS+mana regen> skorn for the extremely rich who can achieve good mit. Id say good mit is around 88%.
it would make more sense if you think of the dmg increasing based upon how many ticks have occured and not a timer. Its easier for the game to calculate dps increase that way vs a timer which I dont think even starts each time COB is casted.
however, for a plague bats build, the 2h is>> than 1h due to it being a DOT.
CoB scales with IAS nicely but the mana use doesnt, that is the truth.