It irks me that we've had all this character development for Illidan. We knew who he was, where he came from, and why he acted the way he did. His motivations, at times, were a little cloudy. Part of me liked that about him. He was an interesting anti-hero.
However, calling him the 'chosen one' gives him this godly plot armor beyond belief. Now any hero or individual that disagrees with Illidan will automatically look like a colossal moron, even if realistically their quarrels with him are completely justified. Illidan is the ultimate good in the universe now and there was nothing wrong with what he did. He essentially gets a 'get out of redemption free card'.
I wanted to see Illidan redeem himself. I really did. This is absolutely not a redemption story. This is telling us that Illidan was good and "has nothing to prove to us and doesn't have to anymore. Anyone who thinks otherwise is an idiot! LOL" It ticks me beyond belief and it's such a missed opportunity. Illidan used to be one of my favorite characters.