One of the potential concerns is that the Kinect will always be on in some capacity as it is listening for the "Xbox On" command. Some are a bit perturbed at the idea of a camera/microphone in their home that is always on.
Personally, I'd have certain concerns about it's size and where to put the damn thing.
Other than it's lack of practical functionality in a room my size, one of the reasons I packed Kinect away was because of it's size and lack of secure place to keep it.
Made all the more difficult with how thin modern TV's are, so you can't just stick it on top easily.

: well, everyone is different; also they obviously want you to use their thing
: instead of those other things

This forms the basis of saying they are sacrificing game support.
All the time, effort and resources they have poured into these aspects is time and money that has not been put into the gaming aspects of the machine.
This is a particular sticking point if you happen to live outside the US, where a number of these features, such as the likes of integrated sports features, may not even be present at all.
Also, Xbox Live isn't available everywhere.