An idea isn't worth much. It hasn't been evaluated, assessed or shared widely. When it is, showing people will pay attention, it becomes an option. While something remains an idea or unelaborated and unexamined option, it won't have a wiki page to describe it. On talk pages it's common to link to the name one is proposing for the option - but that name is not the name of the option it's the name of the idea, so creating a page for it right away is unwise.
As long as the idea or option isn't being pursued, it's effective simply to redirect to the same page that raises it - to anchor pages. See self-link for more detailed discussion of these. Since wiki software can detect such links easily, it becomes easy to determine unpursued ideas.
As the idea develops into a legitimate option, via research and dialogue, it will acquire a stable name, illustrate one or more issues, and one or more detailed positions will be taken. These positions can be combined into a comprehensive policy once it's clear which positions cohere best for each faction that cares. This debate belongs directly in the project namespace if the project is very small, in a policy namespace if it's more formal and requires comparison with others, and in a position namespace if an organization protocol relying on IPA is in effect for this kind of decision making in this kind of venue.