Having had the RT, Pro, Pro 2 and now the Pro 3 I think they have made a few mistakes with the 3, if I had come straight in on a Pro 3 then fair enough but having had the other the 3 is missing a few key things.
Pen, clips to keyboard, if I'm using it as a tablet, then I'll want my pen, which is connected to my keyboard, which if I am using it as a tablet, will be in my bag, with the pen connected to it...
Screen, the screen looks really nice, until you press hard and you get the rainbow effects, not good for a premium device.
I hope the 4 has a thicker glass screen so it doesnt rainbow, I hope they also sort out the pen cliping to the device properly, theres already a magnet where the power is, it wouldnt take long to make that into something the pen could connect to properly..