... off topic deleted...
1 An identical UI experience is not necessary in all circumstances, and many have voiced opinions on the challenges of conforming the experiences you get on a 5" and a 27" screen.
2 Nevertheless, a unified OS will achieve more consistency in the UI experience among all devices and many users will undoubtedly appreciate that.
3 Actually using the same programs will be a benefit--a huge one. If I can use my time and billing program, for example, on my desktop, tablet and mobile phone, that is a huge improvement over the current situation. If the MS Office experience is more consistent among all devices, the user wins.
4 I'm not sure why you've convinced yourself that there are few applications that would be used on both mobile and desktop. That doesn't really make sense, other than it describes the current limited landscape.
1 ya I imagine that's going to be a good challenge
2 yup, if they like the ui , they'll get a bunch of it on all their screens
3 yup ! office suites work pretty good already got me. edit/share/sync, etc, I really like the flexibility of using the best performing office suite on each type of device right now.
4 I'm going by my own usages...
PC:
photo editing
video editing
typical office suite uses involving a keyboard, multiple tabs in chrome, lots of document types at once etc
movie playback/htpc
huge file sizes in torrents/sftp/afp/smb/etc
disk imaging
phone/tablet:
very GPS centric...
GPS enabled mapping, tracking, routing, planning
geo referenced PDFs
osm data uplink
video calls
photography
none of those really cross over in device usage. sure, I can share gigs of videos and maps over Wi-Fi to the htpc, but that's about as close as I get to cross application usage.
honestly I can't think of anything that I do from both screens besides web browsing , forums , email and SMS.