The Recent Files list works as a Recent Files list should. Using Recent Files versus Tabs means an extra keystroke and the time loss of finding the filename. I can live with this for now, but prefer tabs. 

For PHP applications running on Apache, there are .htaccess files which can be used multiple times in an application to grant or deny access to various folders. So an ignore list is really a necessity. In some cases, these files are also used to enable or disable php.ini settings. Thus, they can in some circumstances be a vital part of an application.

Adrien's example suggests one example, but those of us who do object oriented programming using a multi-tiered framework like MVC, HMVC, or PAC often need to quickly move between the files of triads to make changes in other files. For example, for an MVC application, you might need to update the Controller file or View file after making changes to the Model file. 

Another example, creating a new Controller file based on an existing Controller file and moving back are forth between the two files while cutting and pasting code. There are an infinite number of similar scenarios where it would be beneficial to have a tabbed interface or something similar. Keep in mind that the two files might reside in different directories making the cut and paste operations very tedious using the present interface.

For Windows, there is a commercial application called BeyondCompare and an open source application called WinMerge. Both applications show two files side by side along with their line numbers. It's possible to select blocks of code from either window and move it to the opposite window and save the two files separately after completing changes. The general operation of the programs is simple and intuitive. I mention this only from the standpoint of using the general concept as a possible solution. However, a standalone application with the same functionality is also possible. For example, if Textastic supported optional ad-on modules, such a module could be offered as an upgrade.

Kudos for Textastic. It's the best code editor for the iPad.

I noticed that Kodiak Javascript now supports Dropbox and assume that Kodiak PHP will also support it in an upcoming update. Neither of these editors comes close to supporting the Textastic feature set, but they could be used as containers for running PHP or Javascript code once Dropbox support is fully implemented..