David Sparks makes a really good argument for why Microsoft needs to develop iOS versions of Microsoft Office. I agree.

I see several risks Microsoft brings on itself by avoiding iOS development.

The alienation risk

Today, in 2011, many, many Office users are also iPad owners. These people want an easy way to view and make light edits to Office documents on their iPad. (I know because I work in an industry addicted to Microsoft Office.)

By ignoring a platform that so many of its customers are adopting, Microsoft is doing a disservice to its existing customer base.

The ‘I thought things would never change’ risk

Microsoft Office was an extraordinary success for Microsoft. But it requires a PC (in the most general sense). PC sales are slowing, while mobile hardware sales are skyrocketing.

The iPad is in its own category somewhere between mobile and desktop, but I personally feel like it’s closer to the desktop experience than “phone” experience.

Today, few people see the iPad as a full replacement for the desktop experience—particularly for heavy productivity. I think this will change. The iPad will evolve. It will become more powerful and more capable. And cloud services will become more accessible.

The iPad of tomorrow coupled with the increasing ubiquity and versatility of remote servers will, I think, marginalize the traditional desktop in a way that can only hurt the current rendition of Office, which runs locally on a PC.

The 'what if Metro flops?' risk

Just think about the track record of Windows tablets so far. Yeah. Enough said.

The ship without a sea risk

I think of hardware and software being like seas and ships, respectively. A ship is designed to run on a sea—to explore it. A sea must precede a ship, and it also defines the boundaries within which the ship can sail.

The iPad is like a new sea that’s just been discovered. People want to explore the hell out of it. Because that’s what humankind likes to do with newfound spaces.

Like David said, Microsoft is a software company, a maker of ships. Can Microsoft prosper if its ships only sail in seas of yore? I think we all know the answer.