While I miss the quick camera access feature of the physical button, I miss the ability to hold the phone steady with two hands and "snap" a shot more so. There is something that is a bit strange about holding the phone in two hands, but having to have one finger free to touch the on screen button. That said, the camera is FAST on the M8 so blur isn't quite the problem that it might be on some exposures.
At first, that was my biggest complaint about the M8WP, but since then, the speed of the innards, the performance of the hardware and the quality of the build has easily made it my daily driver. I haven't had a phone that I liked this much since the Titan.
That said, I do hope they bring a few more gestures to the table in the future, like maybe a swipe to the right to unlock the camera? Hey, I can dream right?