>>535460540
My theory covers that too:
>Daelin learns the truth about Thrall being an Alliance plant and, respecting the Old Horde as honorable combatants, sails to Kalimdor to show the orcs the truth about their leader
>Tells Jaina that the orcs - referring to Thrall - cannot be trusted
>Tells Jaina: I understand more than you suspect - a very vague and odd line, until you realise he is referring to the truth about Thrall
>Tells Jaina: They must be exterminated like the mongrels they are! - referring to half-breeds like Rexxar, who is also an Alliance plant to promote race-mixing amongst the Horde to dilute orc blood
>Thrall - a notorious pacifist - makes no attempt to parley with Daelin, instead launching an all-out assault on Theramore, with the only goal being the death of Daelin and his troops
>Before he dies, Daelin asks Thrall if he can cast aside his guilt so easily - referring to Thrall's deception of the orcs.

Daelin was a good guy all along, and he paid the ultimate price for it.