wouldn't say this is CLI, more like search as navigation.
Remember that you still have to type and it's far less comfortable on a mobile device. Your concept is interesting, though and in fact it has its realization right now — remember Google Now, Siri and Hound. This is the future. Voice commands.
A few people say voice commands are the future, but what about environments where you don't have the liberty of speaking out loud, or, you don't want to speak out loud—but would still like an advanced input interface?
This makes sense and would be an awesome feature when all apps could be accessible through a single command line.
Perhaps there's room for an app that relies on custom URL schemes to do this? Effectively the Workflow app with a CLI. I think other apps exist where you can string custom URL schemes together like Drafts.
Edit: The app linked to by Cory is kind of this though instead of using custom URL schemes, it directly uses the APIs.
Similar idea: http://input-app.com
Interesting. As more of the world becomes more familiar with computers, concepts like this could catch on.
Similar to digit.co in a sense. Where all commands are done via text.
Voice control is essentially the modern version of the command line.
The makers of siri are working on this : http://www.wired.com/2014/08/viv/
In my opinion, using commands as a form of navigation is a step backwards (moving back to the first computers, which supported only command-line navigation).
I do agree with some of the other commenters in this thread, though, that a potential area for rapid expansion with mobile devices is voice commands. I'd like to take that a step further and say that a potential area for rapid expansion would be voice commands + text interfaces that actually work.
For example, most of the text interfaces out there right now still require a very syntactic approach (Amazon's Echo is a good example, requiring you to say things in a specific way to be picked up). It'll be revolutionary once we get to a point where we can just talk to our devices, either through something like text message or voice commands, and the device can understand us and respond to our inquiries.
That, couple with the current UI design trends (simple, non-complex interfaces) creates a very nice future. You use the text apps for general everyday inquiries, and use the app with the UI when you don't feel like using text messages or voice.
I still think there is space for this as people do not want to be talking to their phones.