Not really. There are some things you cannot build with DX8 but anything that can't be achieved using DX8, a developer can use custom code.
From a templating point of view, DX8 is designed primarily to generate content entity templates, view templates, breadcrumb templates and menu templates. Support for templating custom controllers (such as the Drupal login page or custom controllers defined by other modules) is limited to applying a wrapping template. There is currently no support to create templates for forms. Developers are advised to use webforms or implement a custom controller and use a DX8 wrapping template.