Maybe it's just my preference for squishy characters, but Illidan feels a bit over the top right now. He's just got too much self sustain and mobility, it's really fucking hard to get him locked down without coordinating multiple stuns. He almost feels like a melee LM - not in the snowballing respect, but in that he can just keep going and going unless your entire team stops to shut him down.
Sure there are still a lot of Illifeed players who'll dive in 1v3 or hunt into stupid positions or whatever and get farmed, but a good Illidan is a huge pain in the arse right now, put a decent healer/abathur behind them and they're a certifiable nightmare.
But I might be a little biased, since I like playing squishies - one the bright side, it's given me an excuse to work on my tank game, and I've finally started really getting into Johanna.