It’s more accurate to consider the iPhone a computer than a phone. Perhaps even more so for the iPad.

Clearly Apple sees this as well, as the evolution of iOS makes clear. From its no apps, iTunes-required beginnings to the 700,000+ apps, no-iTunes-required current state iOS has been steadily marching towards becoming a full-fledged computer. But it isn’t there yet. So what remains? Here’s my list.

Fonts

If the iPad is to become the computer of the future you’re going to need to be able to install fonts on it. What I’d really love to see is fonts synced via iCloud between my Mac and all my devices. I have to believe that Apple eventually wants at least their own apps, like Pages, to have complete parity between the Mac and iOS versions. No more “Some formatting is not supported. Would you like to create a copy?” messages when opening a Pages document on iOS that was created on the Mac. To get there they will have to let you install and manage your fonts.

System Defaults

The utility of third-party browsers, email clients, and (now especially) mapping apps is dramatically reduced by iOS’s total ignorance of them. If you click a link that opens in a browser, that browser is going to be Safari, even if you have Chrome or Dolphin in your dock. Clicking an email address is going to launch Mail, even if you have Sparrow installed. As the offerings in the App Store grow in sophistication this situation is going to become more and more untenable, especially when competing platforms (cough Android cough) have no such limitations.

Inter-app Communication

Both Android and Windows 8 have implemented models for inter-app communication that are far superior to iOS. That is to say, they actually have a model. Apple has seemingly laid the groundwork for a solution to this with XPC, but we’ll have to wait and see. This is another one that will become more and more problematic (unless Apple solves it, of course) as the third-party app market matures and the needs of iOS users multiply and diversify.

File Management

This could be the one that Apple doesn’t budge on. I continue to believe that without a central document store, accessible by any and all apps on the device, the long-term potential of iOS is crippled. However Apple may continue to push and tweak their total sandbox approach until either it becomes clear it’s good enough, or competition forces them to shift strategies.

Multi-User Capabilities

Here’s another feature that Apple may never bring to iOS: the ability to have more than one user on a device, each with their own apps and accounts. It certainly seems a little premature given the current storage sizes (two users sharing 16 GB? No thanks.), but as the capacities move into the 100+ GB range this starts to make sense.

Market Maturity

One of the biggest reasons iOS devices aren’t full-fledged computers yet is because the market still says they aren’t. Yes, the lack of the features I’ve listed here (and many others, I’m sure) make it more difficult to bring traditional desktop applications to iOS. But it’s not impossible. For example, as far as I can tell, there isn’t a single app on the app store for managing SVN or Git repositories akin to Cornerstone or Versions on the Mac. Why? Probably because the assumption is that no one wants to manage those things on their phone. That’s what you’ve got a computer for! Well, I’m holding a tiny computer in my hands right now, typing out this blog post. Everyone might not see it that way now, but in five years? Ten years? The direction is clear; our arrival certain. The only question is how fast we get there.