"The big question is what's Microsoft's mobile strategy beyond Windows," Rotman Epps said. "It leaves Office open to disruption."
For example, particular threats are productivity suites that, despite lacking the comprehensive feature set of Office, work on iOS and Android devices, like Google's Quickoffice, she said.
Another area where Microsoft can improve is in simplifying the bundling and licensing of Office 365, which now encompasses many options, variables and packages for consumers, SMBs, enterprises, government agencies and schools.
In this area, Google Apps has managed to appeal to customers attracted by its simpler and more streamlined offer with fewer packages and straightforward pricing, said Guy Creese, a Gartner analyst.
"Microsoft should be using the cloud as an opportunity to simplify things and it isn't," Creese said. "It's better than it was, but not as clean as it could be."
A big, unanswered question is price. Office has historically not been cheap, and with the increasing pressure from free and inexpensive alternatives, the issue has become a critical element for consumer and workplace buyers.
"The shoe waiting to drop is how much it's going to cost," Creese said. "It's the part everyone wants to know before making a decision to purchase it or not."
The new subscription-based model, in which customers pay a monthly or annual fee instead of one up-front payment, could cut both ways.
The option to pay a smaller amount every month or every year, along with the five-device license and the automatic upgrades, could entice some buyers who have been put off by the perpetual license price.
However, depending on the monthly or annual fee, it could be a disincentive as well, especially for buyers who find the subscription payments adding up over time, Creese said.
Microsoft didn't announce a shipping date for the new Office. Windows 8 will ship in October.
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