I'm scared about ML either. It has sth that keeps your machine on when you close the lid! Gets some update, notification stuff. What if it happens there when you put you machine inside a bag?! The power nap thing is kind of scary when you have a problem like this. No way you're going to trust sleep again when this is happening now.
My friend in French, happened to him two weeks ago. He has Macbook. It burnt upper board, keyboard, and power button. 200 Euro! They told him you should always check your light indicator.
You right Apple. We should always check the light indicator. MBPR doesn't have one because you think it doesn't need one. But it seems to me it does. And one more thing, Apple should always turn off the whole computer when it passes from a critical temp! Not let the heat burns everything. A 10-year old computer does that 🙂 But poor guy paid the money and waited for one week.