A bit of background ...
1. Hololens IS a kinect on the face, that's how it track surface from reality.
2. The failure of the kinect was the lag due to image analysis and low refresh rate from the camera (30fps), the Hololens has a dedicated and powerful FPGA for image analysis, on top of an actual gp/cpu combo.
3. Don't expect the 40 degree FOV to improve any sooner, each time you double the size the processing power need to go 4 times bigger and the power consumption/heats follows, it's on battery and on your head.
4. It has the same technical constrain than vr in term of latency, so it's a refresh rate of +90hz or bust, which limit a lot the processing power available.
The size of the field of view is basically that of a ipad at arm's length.
It's equivalent to look at a 102cm TV at 3m
It also allow high density of pixel
They show it there
http://i.imgur.com/xzGxaZH.pngSimulation of teh fov
The fov on the glass itself
It's a bit more sophisticate than that
It actually track a 3D scene instead of edge on a flat image, have better tracking fideliy, and the screen is see through.
In fact if we succeed in aligning camera FOV on top of a VR headset so that the focal point and FOV align with the real eyes, it might be the goto solution.
BUT both VR and hololens need to deal with actual real life DOF as the eyes focus on a point in depth