at what point can we consider the development of "set this element's text/html" to be done?

When browsers implement a variant that lets you separate data and code perhaps. That's what I expected when reading the headline: setHtml(code, data, data, ...), just like parameterised SQL works: prepare("select rowid from %s where time < %n", tablename, mynumber)

This new method they've cooked up would be called eval(code,options) if html was anything other than a markup language