I'm planning to create a macOS applicaiton for doing textual analysis. For example, it would open a text file and then create a statistical display of word distributions, character frequencies, and so on. The app would not allow editing of any of the files it opens, but it might save versions of those files that have changes to the original (e.g. encrypted versions). I'll start with plain ASCII text files, but evenutally I would like to expand the app to handle RTF, HTML, PDF, ePUB, etc.
So finally, my question: Should I initially create this as a document-based app using the Xcode template? Or would that needlessly complicate things? (Obviously, I haven't yet had any useful experience with document-based apps!)
The Document template gives you a lot of features for free which may be useful for you (things like the recent file menu, etc.). The bigger question should be, are you going to be opening multiple files at the same time? If so, then the document based approach can help a lot. If, however, you are opening one file, working on it, closing it to open another, etc., then I would not use the document approach.