Microsoft is making big, bold bets on its new operating system, Windows 8, which is set for release later this year.

Windows 8 is, in large part, Microsoft’s response to a world that is increasingly mobile, and in which tablet devices may be competing with desktops for consumers’ computing time.

Perhaps not surprisingly, industry observers seem split on Microsoft’s chances of success with Windows 8. Some like where the company is going, and think Microsoft’s focus on touch-enabled devices is the right one. But others think the Redmond software giant is taking too big a risk and won’t be able to execute.

Who is right? The answer may be determined by the supporting cast: the software available for Windows 8. Microsoft is hoping developers flock to the Windows Store, but it also has a formidable asset in Office, the ubiquitous application suite used by countless consumers and businesses. And today, Microsoft made it clear: it will use Office as a weapon as it battles to maintain its position in the computing landscape.

The new version of Office Microsoft unveiled today is a “touch everywhere” application designed for touch and stylus-based input. There a social features, such as integration with Skype and Yammer. And a new API will allow developers to build Office add-ons using JavaScript and HTML5.

But the biggest changes to Office relate to the way it’s sold and delivered:

  • Windows RT devices, which include Microsoft’s Surface tablet, will be sold with a version of Office, dubbed Office Home and Student 2013 RT, bundled.
  • Office 2013 will be sold as a cloud-based subscription offering that comes in three flavors. According to Microsoft, “each new subscription offer will include the new 2013 editions of the Office applications — Word, Excel, PowerPoint, OneNote, Outlook, Publisher and Access. In addition, subscribers will receive future rights to version upgrades as well as per-use rights across up to five PCs or Macs and mobile devices.”

As Ars Technica’s Sean Gallagher succinctly puts it, “Microsoft is clearly counting on Office 2013 to be a fulcrum point for the company’s whole Windows and cloud platform strategy: moving from a PC-centric worldview to an ecosystem of devices; moving from older Windows versions to Windows 8; and moving from software sales toward cloud-driven subscriptions.”

The big question: can Microsoft pull it off? Microsoft deserves credit for making such bold moves, but the bolder the get, the riskier they seem as well. The company’s desire to sell Office on a subscription basis, and integrate it with the cloud, is a substantial shift — one that consumers and businesses may or may not be so amenable to.

Which highlights perhaps the biggest challenge for Microsoft with Windows 8 and Office 13: convincing consumers that its changes are a good thing. Clearly, Microsoft has convinced itself of that, something that is often difficult for entrenched players in any industry to do. But as much as consumers often say they want change, delivering it successfully can be very, very tough.