I had a look at Meslo. It looks like the author just took Apple's font and modified it. Menlo is copyrighted by Apple, so that sounds fishy...

It seems like iOS 8 includes Apple's Menlo font though, so I plan to include that.

Well, I added external files that are opened through the "Open…" command to the recent files list exactly for that reason. If the file does not exist anymore, it is not displayed in the list of recent files.

I figured it would only confuse the user if external files shows up next to iCloud files, especially if you have a lot of files in iCloud.

I would also like to display more information in the recent files list (like the file path or external app name), but this information is not available with the current iOS APIs.

On Yosemite this might indeed be a good solution if you don't want to save new files in iCloud.

The problem is that .as is already used by ActionScript (Flash), which is probably the more popular language. If you select MEL manually from the syntax definition list for a .as file, all .as files will use this syntax definitions in the future.

The document picker is completely provided by iOS and can't be customized (including the storage provider selection menu), so it would be up to Apple to improve it. Maybe in iOS 9? :)

I've worked closely with the author of Working Copy. Version 1.2 of Working Copy is currently waiting for review at Apple, but is required to properly work with Textastic. I hope it gets approved soon.