I'd recommend having its own repository with Markdown files grouped by target domain using tags for every card. It'd help to search quickly relevant cards even in the same domain.
I use a custom text file format to allow creation of cloze deletions and reversible cards as well as basic cards. I also annotate text files on export so that I can export the file again without creating duplicate cards.
The big shortcoming of my script is that it generates .tsv files and Anki only allows .tsv files to contain one note type. They also do not incorporate media.
I'd like to be able to sync edits made in Anki back to the text files and vice versa. It'd be really cool to integrate a text file parser and alternative card editing mode into Anki with a plugin.
Perhaps I'll send some PR's your way instead of duplicating effort.