The detractor IMO is it's designed/aimed at social network users ie Facebook. Automatic deal killer. But the appeal is there for those that use that sort of nonsense.
I've heard this criticism before, but I've yet to hear with any specificity how, exactly, their FB integration detracts from the device's overall functionality. In other words, I don't see how it's especially true, or if it were, how it's relevant. Not trying to be a fanboy, but if you have anything specific in mind I'd like to hear it.
I just don't see it being as flexible or configurable as an Android phone.
Maybe. MS did set rigid hardware guidelines at the outset, so my suspicion is that they simply haven't written the APIs for the accelerometer, compass, and camera for all the OEMs yet. My instinct tells me they will, because there doesn't seem to be any business or political reason not to, and they'll be necessary for a competitive apps market. Also, it's not the UI clusterduck that Android is, so ya takes the good and takes the bad, I suppose.
The one thing that does concern me is the lack of tethering and hotspotting support. That does seem like something important that just might never materialize.