I was watching those videos for developers about the new SDK, and from what I understood "Universal apps" is not a new technology, there is nothing special about it. Just the same Universal apps of Windows 8 with a few improvements. There was no mention of any support for productivity apps in this framework, It's still touch centric.
The same could be said about Windows 10. It's just Windows 7 plus tiles, Cortana and notifications. Windows 10 mobile is just Windows Phone 8.1 with hamburger menus :grin:. In contrast, Windows Phone 7 and Windows 8 were such a big departures from their previous versions.
It would be surreal if a few tweaks here and there would be enough to save Windows from oblivion.
https://channel9.msdn.com/Series/Developers-Guide-to-Windows-10-Preview