This task involves the work with implementing a way for people to return to the legacy "New topic" workflow without needing adjust the state of the Enable quick topic adding setting within Special:Preferences.

User Story

As a Senior Contributor who has the New Discussion Tool enabled, I want to be able to easily switch back to the legacy section=new experience from within the New Discussion Tool on a case-by-case basis, so that I can use a particular gadget/use some complex subst template [example(s) needed] without needing to expel the effort to visit Special:Preferences and adjust the state of the Enable quick topic adding setting.

Thank you to @Tacsipacsi (source), @Honischboy (source), and @Teemeah (source) for voicing this need at mediawiki.org.