Has no one else had this problem? Today was the fourth time that this has occurred after a system suspend (I have never used the hibernate state with the NUC), which required having to disconnect the CMOS battery. This is frustrating and will lead to something breaking, eventually.
I have a similar setup (D54250WYKH, Ubuntu 14.01.1 x64). In my case, the power button would have no effect in waking the system. After unplugging the power supply, the power button or activity light would show a faint green. Plugging in a USB key would cause it to blink a few times and then nothing. Only after pulling the CMOS battery for a few seconds would my problem be resolved. I've tested two different hard drives, so I doubt this would have any effect.
Note, I have just updated the BIOS from revision 30 to 32 which makes changes to the C9/C10 power states. Hopefully, this resolves the problem. I will monitor this issue.
Here's a suggestion to Intel. In a future revision, please include a quick CMOS reset button / pin hole. This may resolve many an RMA / warranty issue.