Editors decide: templates
Templates need no code. A template renders by its kind: a view template renders its view, a
controller template its action, and a Razor Page template its page (chapter 5). A
kind of your own renders as you say (below). A page without a
template gets the template made for its type: the one whose NodeTypes is closest to the page's
type, chosen the same way as code defaults.
So when every page of a type looks the same, one template for the type is enough. To let editors choose, make more than one template for the type. A page must then choose, since neither template is closer than the other:
templates "article" and "article-wide", both for IArticle
an IArticle with Template = "article-wide" → ArticleWide.cshtml
an IArticle with Template = "article" → Article.cshtml
an IArticle with no template → error: both fit equally, so the page has to chooseThe CMS refuses to save such a page without a template, so editors see the problem, not visitors.