The impeccably Softie-sourced Tom Warren has another scoop out of Redmond: that Microsoft indeed has plans for MS Office for iOS and Android, and that we can see them as soon as the first half of 2013. iOS is likely to get them sooner, perhaps in March, with Android right behind, in May.

Warren gives some more details about the logistics of the apps: there will be free apps to let users view MS Office documents, though you’ll need to sign up for a Microsoft account. If you want to be able to edit them on the go, you’ll have to get an Office 365 subscription. It’s rather clever of Microsoft to turn what we traditionally think of as a one-time purchase into a subscription model. You want to be in the business of selling razor blades, not razors, and the land of mobile and cloud computing, in which everything is viewed as a service, is increasingly enabling that.

The main thing you should probably know about MS Office for iOS and Android is that you may be disappointed if you’re expecting something transformative. Not only does Warren tell us in his Verge post that the apps “won’t go very far in attempting to replace regular full use of a desktop Office version,” but we also have the experience of Surface tablet users, who have experimented with a Windows RT-enabled version of MS Office 2013. CNN’s reviewer, for instance, called the Office suite one Surface “the least satisfying thing” about the tablet.

“They’re the one part of this product Microsoft hasn’t reimagined,” he wrote. It’s a pretty damning criticism, actually, when you consider the fact that the Surface is being touted as the tablet that can switch-hit as a laptop replacement, what with its physical keyboard-cover hybrid. CNN wrote that Office for the Surface merely gave a Windows 8 sheen to the product, rather than really rethinking it from the ground up. “They work, but the whole experience feels like an exercise in compromise,” alas, concluded the reviewer.

I’ve long argued that an MS Office app could finally nudge tablets towards being real productivity devices (see “An iPad MS Office?”). But if Microsoft wants to really sell its Surface tablet as a cure-all for the tensions between computing and mobility, it needs to nail its mobile version of Office. It needs to be the most satisfying thing about the tablet experience, if that’s at all possible.