This is exactly what I posted a week ago after canceling my pre-order . IMO, the keyboard experience is very, very lacking... for people like me who type a lot, this is a huge deal breaker. This, in no way, is a MBA killer. If they put in as much energy as they did in the upper body to build a top-notch keyboard as a dock, I'll gladly pay them $1500-2000.
Although, I'll say this: for people who are not into typing a lot, this would make an amazing machine.
I type quite a bit, and find the keyboard across the Type covers to be fine. The shallowness may need some getting used to if you are used to a deeper depression (think like going from a vehicle's manual shifter with large shifting moments, to a vehicle with shorter, shifting moments of a manual transmission). It is quite fine, and capable.
It may feel flimsy, but it shouldn't hamper anything at the very least, other than seem off at first. Though much like my comment in the paragraph above, one would need to accomodate to not slam their fingers to the keys.
With the keyboard, I can basically type in any sitting orientation, outside of a solid desk or table surface even. I had no problems typing indian style with the device cradled in my legs.
I would say with the Tablet PC/Hybrid design - with the hardware located at the top, this means all of that possible heat isn't on one's legs if one is using the kickstand. But with the Surface Pro 3, the significant amount of heat is generated when taxing to the maximum processing capability.
I also would say that in a kickstand design, one isn't inclined to really push the device to the tip of their knees for use, given a needed leg runway - a tradeoff with the convertible design which is why I want more OEMS to adopt to what Lenovo has with the Yoga like devices, but have a pen (Wacom would be nice but if implemented as nicely as N-Trig with the Surface Pro 3 but having an eraser end would be almost just as nice).
A tradeoff with a solely laptop design - I can't draw or write directly on the screen with a pen device. If I touch it if a laptop has a touch screen, it is no different than touching and interacting with a Type cover in that flimsiness.
At the very least, I want Wacom and their next Cintiq Companion to up their game with a matching or better screen than the Surface Pro 2 (I said 2 because I find that screen to be a bit better), in almost the same size in foot print, with their top digitizer in them. Coupled with Type cover compatibility with Microsoft, it would be a sure win with them (As I do not like their solution for a keyboard).