The Xbox One is an engineering disaster for a custom made consumer product that isn't intended to be user serviceable. It's like a "Holy $@#^ we forgot that we are making a next-gen console, gotta ship this thing to stores before Holidays 2013, so just slap everything up with no thought whatsoever" hackjob.
-Why use a huge Intel retail type HSF instead of a custom cooling solution like the PS4 did?
-Why is the HDD placed completely inside the case in a manner that wastes unnecessary space and prevent users from accessing it from the outside?
-Why is the motherboard so big? There are lots of wasted PCB space that can be cut.
-Why even use a standard PC sized optical drive?
-If all those wasn't enough yet, add a external power brick to it. Again.
Before somebody tries to flame me, please explain how Valve was able to make a smaller machine with completely off-the-shelf-parts including the PSU and a GTX 780, yet much more powerful in CPU/GPU power and infinitely more user serviceable.