Well...
Maiev says: It is finished. You are beaten.
Illidan says: You have won...Maiev. But the huntress...is nothing without the hunt. You...are nothing...without me.
Maiev says: He's right. I feel nothing. I am nothing. Farewell, champions.
The implication is that we leave Maiev there with Illidan. We can infer that the Illidari return just after we have left.
Also Illidan is dead, insofar as his soul hasn't come back to his body.
It's not a retcon in the strictest sense, just sloppy writing.