Deathwing alone achieved much more then both Archimonde and Kil' Jaeden(They had an army of millions and still barely even came close to succeeding(They did not cause the sundering so don't use that to back you up)), so I wouldn't say that. Also, Archimonde was afraid of Deathwing before AND after he had gotten the dragon soul. And ANOTHER thing to add, in order to destroy Deathwing, it took the power of an ancient and powerful demon artifact to just wipe off his armor, then it took the power of ALL the dragon aspects PLUS the most powerful living shaman on Azeroth to kill him. Archimonde died from a bunch of puny whisps... Lame.
And during the War of the Ancients, N'Zoth WANTED Sargeras to come on Azeroth so he would do enough damage to free him, and not for Sargeras to kick his ass back to his prison, but so N'Zoth can kill him and most probably attempt to take over the Legion to make his plans succeed. It took armies of Titans to only imprison 5 Old Gods whom were all against each other, and both sides most probably suffered tragic loss. Sargeras is not as powerful as everyone interprets him to be, so that's why he sends his bitch to all his work(Kil'Jaeden) who then sent his bitch(Illidan) to do his work.
Plus, there was even a quote from I think Brann Bronebeard, saying whatever lied underneath the Barrens, if it ever were to be freed, even Sargeras would plead for a peaceful death. And obviously it was an Old God imprisoned underneath the Titan facility and N'Zoth is known to be the most powerful Old God on Azeroth. Not only that, he has pretty much Azshara working for him as well who is also said to be as powerful as Kil'Jaeden and Archimonde. I don't see where all the Sargeras hype came from, he didn't really do anything so far.(Yes I know, is leader of a army of millions, but him physically)