But what is still missing is a Metro version of Office. Historically, Office has always been the showcase on how to build proper Windows applications, it's where UI innovations are first introduced: i.e. embedding, multiple document interface, icon bar, ribbon.
Since the introduction of the Metro ('modern') UI, Microsoft has not been able to really show the power and possibilities of it. Office for Metro should fix this, and show people how Metro is superior to the iOS and Android UI. Supposedly Office Metro has been in development for years (project Gemini), but as it turns out: it's not ready. And Office for iPad is.
I hope we'll hear more about office for Metro soon, maybe next week at Build?