Instead of being rebuilt as Metro apps using WinRT programming, Office 15 will feature a radial menu system and a flatter, cleaner design that will mask what will be traditional Windows apps.
It's not what the company wanted, it seems, but time is working against it.
One source told The Verge that plans to create Office in true Metro style had to be pushed back "as the Office team would have to overhaul the entire suite to take advantage of WinRT" which would take far too long.
Some less complicated elements of Office 15 will be coming out as true Metro apps, however: OneNote and Lync are both expected to hit the Windows Store in their own rights.
This gives us hope that a true WebRT version of the Office suite could yet be in the pipeline – but we're definitely not holding our breath.
Office 15 went into private technical preview earlier this week, with a public beta to follow in the summer.
From The Verge