So I take it you are not very happy with the M8 that you are holding on to right now?
I for one agree with you with regards to the placement of the power button. But that problem is alleviated slightly with motion launch. The power button is still necessary to lock the phone. Double tapping to lock the phone only works when you at the lock screen. I understand you can double tap to lock the phone anywhere in the LG G2's interface?
Motion launch can be quite annoying at times as certain commands can be triggered accidentally. They should allow the user to disable specific motion launches. I keep opening the camera app by accident when I am adjusting the volume when listening to music.
I don't like the black bar below the screen as well. They said it provides space to house the components but I think that is a bulls**t excuse. What about the other phones with very little bezels like the G2, Galaxy S4 and Nexus 5? They shouldn't have moved the buttons on screen, if they were going to keep the black bar. It effectively makes the 5 inch screen on the M8 less than 5 inch as there is no immersion mode in most apps. The black bar is just wasted space. They could have at least made it narrower. They already have a HTC logo on the back, why do they need one on the front? Seems this is the same case with most Android manufacturers, having a logo on the front and back.
I like how iPhones only have the logo on the back. It makes the device look much more elegant, without so much clutter.
Anyway, just my two cents