I think I would be fine with somewhat of a middle-ground. I would prefer that HTML be in templates, but I'm also fine with those templates **not** being in the served page, and only fetched and used as needed. (Or in the case of nunjucks, you don't even have to waste an AJAX call since templates get precompiled into a .js file.) I just prefer html to be in a .html file, and javascript to be in a .js as much as possible. I think it simplifies things, helps prevents silly mistakes and oversights, and helps newcomers to the project orient themselves more quickly.