I think it's only canon on a "that's what ya'all voted" basis. Same with the illustration.
Like Abdal, I expect it will be what is used if there is a novelisation or whatever.
If the site only marks the Dark Urge as a sorcerer because of some community feedback then that is horrible and misleading. I am absolutely convinced that to make the most of the specialized rewards the dark urge gets Rogue Assassin is the way to go...which especially makes sense given the connection to Bhaal. I'd be very careful here with this one. Personally I will treat the "Sorcerer" designation on the website as either a mistake or a red herring unless we get some real evidence as to how Sorcerer makes more sense than Rogue Assassin for the Dark Urge.
