its good as a concept... nothing more.
people complained about an improved start screen because "start menú is better and start screen is not for pc users" (whatever that means), imagine if Microsoft changed totally everything like this concept suggests...
a taskbar really? I can imagine Microsoft improving the way fast switch Works and App previews and such... but someone didnt get the memo that Fullscreen apps arent bad? why would I want to see icons all the time?
and you know... I would rather Microsoft reverting back to "Windows 7" than and stay in desktop forever than that weird scroll through apps things just to say "Windows arent dead" (whatever that means... again)... and it would be for touch only... I can see how it wouldnt work well with mouse users, start screen is nice to scroll through it, but if you are in an App, and you want to change App... what are you gonna do? the purpose of this concept its to scroll trhough them, it sounds silly to go out of the App just to scroll to the other App, and lets hope the scroll doesnt actívate when you are over an App... but how you are going to use it fast enough if you have to go in an out of apps just to scroll through them?... I dont know.
oh and what if my apps its the last one in the list? becuase they dont want icons or tiles to show... Microsoft will throw away all the workd they have done with live tiles and such. well it seems it wont even work with many apps installed... becuase you know... with only the apps that would come preinstalled it would take like 3 hours to scroll through those previews or whatever they are.
again, not a bad concept but Im glad it will stay that way.