You can use the soft power button to shutdown the Pi 2 on OpenElec. However, you can't turn it back on until you recycle the power manually using the power adaptor.
So it's missing a "remote" on/off controller.
If you had a tv with usb port, you can try using it to power the Pi 2, so you can power it on/off together with the tv.
For me, I had a Philips soundbar HTL5140 with usb port.
I connect a cable from that usb port to power the Pi 2.
Now it works like a power on/off remote control when I shut down or power up the soundbar.
However, I lose the use of the usb port input to the soundbar.
Surprisingly it works well, since the video hdmi output goes back into the soundbar.
Using the tv/soundbar usb port to power the Pi 2, you also save on buying a power adaptor.